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  • 1.
    Akbarnejad, Shahin
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad processmetallurgi.
    Saffari Pour, Mohsen
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad processmetallurgi.
    Jonsson, Lage
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad processmetallurgi.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad processmetallurgi.
    Significance of Fluid Bypassing Effect on Darcy and Non-Darcy Permeability Parameters of Ceramic Foam FiltersManuskript (preprint) (Annet vitenskapelig)
  • 2.
    Akbarnejad, Shahin
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Saffari Pour, Mohsen
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Jonsson, Lage Tord Ingemar
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Jönsson, Pӓr Göran
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Effect of Fluid Bypassing on the Experimentally Obtained Darcy and Non-Darcy Permeability Parameters of Ceramic Foam Filters2017Inngår i: Metallurgical and materials transactions. B, process metallurgy and materials processing science, ISSN 1073-5615, E-ISSN 1543-1916, Vol. 48, nr 1, s. 197-207Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ceramic foam filters (CFFs) are used to remove solid particles and inclusions from molten metal. In general, molten metal which is poured on the top of a CFF needs to reach a certain height to build the required pressure (metal head) to prime the filter. To estimate the required metal head, it is necessary to obtain permeability coefficients using permeametry experiments. It has been mentioned in the literature that to avoid fluid bypassing, during permeametry, samples need to be sealed. However, the effect of fluid bypassing on the experimentally obtained pressure gradients seems not to be explored. Therefore, in this research, the focus was on studying the effect of fluid bypassing on the experimentally obtained pressure gradients as well as the empirically obtained Darcy and non-Darcy permeability coefficients. Specifically, the aim of the research was to investigate the effect of fluid bypassing on the liquid permeability of 30, 50, and 80 pores per inch (PPI) commercial alumina CFFs. In addition, the experimental data were compared to the numerically modeled findings. Both studies showed that no sealing results in extremely poor estimates of the pressure gradients and Darcy and non-Darcy permeability coefficients for all studied filters. The average deviations between the pressure gradients of the sealed and unsealed 30, 50, and 80 PPI samples were calculated to be 57.2, 56.8, and 61.3 pct. The deviations between the Darcy coefficients of the sealed and unsealed 30, 50, and 80 PPI samples found to be 9, 20, and 31 pct. The deviations between the non-Darcy coefficients of the sealed and unsealed 30, 50, and 80 PPI samples were calculated to be 59, 58, and 63 pct.

  • 3.
    Alsabery, Ammar I.
    et al.
    Islam Univ, Coll Tech Engn, Refrigerat & Air Conditioning Tech Engn Dept, Najaf 54001, Iraq.;Univ Kebangsaan Malaysia, Fac Sci & Technol, Dept Math Sci, Ukm Bangi 43600, Selangor, Malaysia..
    Ghalambaz, Mohammad
    Ton Duc Thang Univ, Metamat Mech Biomech & Multiphys Applicat Res Grp, Ho Chi Minh City 758307, Vietnam.;Ton Duc Thang Univ, Fac Appl Sci, Ho Chi Minh City 758307, Vietnam..
    Armaghani, Taher
    Islamic Azad Univ, Mahdishahr Branch, Dept Engn, Mahdishahr 7591535618, Iran..
    Chamkha, Ali
    Duy Tan Univ, Inst Res & Dev, Da Nang 550000, Vietnam.;Duy Tan Univ, Inst Theoret & Appl Res ITAR, Hanoi 100000, Vietnam..
    Hashim, Ishak
    Univ Kebangsaan Malaysia, Fac Sci & Technol, Dept Math Sci, Ukm Bangi 43600, Selangor, Malaysia..
    Saffari Pour, Mohsen
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap. Shahid Bahonar Univ Kerman, Dept Mech Engn, Kerman 7616914111, Iran.
    Role of Rotating Cylinder toward Mixed Convection inside a Wavy Heated Cavity via Two-Phase Nanofluid Concept2020Inngår i: Nanomaterials, E-ISSN 2079-4991, Vol. 10, nr 6, artikkel-id 1138Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The mixed convection two-phase flow and heat transfer of nanofluids were addressed within a wavy wall enclosure containing a solid rotating cylinder. The annulus area between the cylinder and the enclosure was filled with water-alumina nanofluid. Buongiorno's model was applied to assess the local distribution of nanoparticles in the host fluid. The governing equations for the mass conservation of nanofluid, nanoparticles, and energy conservation in the nanofluid and the rotating cylinder were carried out and converted to a non-dimensional pattern. The finite element technique was utilized for solving the equations numerically. The influence of the undulations, Richardson number, the volume fraction of nanoparticles, rotation direction, and the size of the rotating cylinder were examined on the streamlines, heat transfer rate, and the distribution of nanoparticles. The Brownian motion and thermophoresis forces induced a notable distribution of nanoparticles in the enclosure. The best heat transfer rate was observed for 3% volume fraction of alumina nanoparticles. The optimum number of undulations for the best heat transfer rate depends on the rotation direction of the cylinder. In the case of counterclockwise rotation of the cylinder, a single undulation leads to the best heat transfer rate for nanoparticles volume fraction about 3%. The increase of undulations number traps more nanoparticles near the wavy surface.

  • 4.
    Alsabery, Ammar I.
    et al.
    Islamic Univ, Refrigerat & Air Conditioning Tech Engn Dept, Coll Tech Engn, Najaf 54001, Iraq.;Univ Kebangsaan Malaysia, Fac Sci & Technol, Dept Math Sci, Bangi Selangor 43600, Malaysia..
    Hashim, Ishak
    Univ Kebangsaan Malaysia, Fac Sci & Technol, Dept Math Sci, Bangi Selangor 43600, Malaysia..
    Hajjar, Ahmad
    Univ Lyon, ECAM Lyon, LabECAM, F-69007 Lyon, France..
    Ghalambaz, Mohammad
    Ton Duc Thang Univ, Metamat Biomech & Multiphys Applicat Res Grp, Ho Chi Minh City 758307, Vietnam.;Ton Duc Thang Univ, Fac Sci Appl, Ho Chi Minh City 758307, Vietnam..
    Nadeem, Sohail
    Ton Duc Thang Univ, Math & Its Applicat Life Sci Res Grp, Ho Chi Minh City 758307, Vietnam.;Ton Duc Thang Univ, Fac Math & Stat, Ho Chi Minh City 758307, Vietnam..
    Saffari Pour, Mohsen
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap. Shahid Bahonar Univ Kerman, Dept Mech Engn, Kerman 7616914111, Iran..
    Entropy Generation and Natural Convection Flow of Hybrid Nanofluids in a Partially Divided Wavy Cavity Including Solid Blocks2020Inngår i: Energies, E-ISSN 1996-1073, Vol. 13, nr 11, artikkel-id 2942Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The present investigation addressed the entropy generation, fluid flow, and heat transferregarding Cu-Al2O3-water hybrid nanofluids into a complex shape enclosure containing a hot-halfpartition were addressed. The sidewalls of the enclosure are made of wavy walls including coldisothermal temperature while the upper and lower surfaces remain insulated. The governingequations toward conservation of mass, momentum, and energy were introduced into the formof partial differential equations. The second law of thermodynamic was written for the friction andthermal entropy productions as a function of velocity and temperatures. The governing equationsoccurred molded into a non-dimensional pattern and explained through the finite element method.Outcomes were investigated for Cu-water, Al2O3-water, and Cu-Al2O3-water nanofluids to addressthe effect of using composite nanoparticles toward the flow and temperature patterns and entropygeneration. Findings show that using hybrid nanofluid improves the Nusselt number comparedto simple nanofluids. In the case of low Rayleigh numbers, such enhancement is more evident.Changing the geometrical aspects of the cavity induces different effects toward the entropy generationand Bejan number. Generally, the global entropy generation for Cu-Al2O3-water hybrid nanofluidtakes places between the entropy generation values regarding Cu-water and Al2O3-water nanofluids.

  • 5. Arjmandi, H.
    et al.
    Amiri, P.
    Saffari Pour, Mohsen
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Geometric optimization of a double pipe heat exchanger with combined vortex generator and twisted tape: A CFD and response surface methodology (RSM) study2020Inngår i: Thermal Science and Engineering Progress, ISSN 2451-9049, Vol. 18, artikkel-id 100514Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this research, a numerical investigation is done on the effect of employing the new combined vortex generators, the twisted tape turbulator and Al2O3-H2O nanofluid as the involved base fluid. Such study is carried out on the behavior of the heat transfer rate and the pressure drop of a double pipe heat exchanger. Accordingly, the response surface methodology (RSM) grounded on the central composite design (CCD) is used for acquiring the optimized geometry of the combined vortex generator and twisted tape turbulator. In order to have the maximum Nusselt number and minimum friction factor, twenty cases with different pitches ratio Pil=0.09-0.18, angles (θ=0-30°) and Reynolds numbers (Re = 5000-20000) are examined. The Results show that the pitch ratio has a predominant effect on the Nusselt number and the friction factor, which causes an efficiency increase up to five times compared to the original one. In addition, by decreasing the angle of the vortex generators in the new combined turbulator, both Nusselt number and the friction factor are increased.

  • 6.
    Cuvila, Carlos Alberto
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Kantarelis, Efthymios
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Mellin, Pelle
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Saffaripour, M.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Hye, A.
    Yang, Weihong
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Effect of zeolite on product yield and composition during pyrolysis of hydrothermally pretreated SpruceManuskript (preprint) (Annet vitenskapelig)
  • 7.
    Cuvila, Carlos Alberto
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Said, Mahir
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Kantarelis, Efthymios
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Saffaripour, M.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Yang, Weihong
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Effect of mild hydrothermal pretreatment on biomass pyrolysis characteristics and vapors: A Mass and Energy Balance PerspectiveManuskript (preprint) (Annet vitenskapelig)
  • 8.
    Ghadamgahi, Mersedeh
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik. Ovako Hofors AB, Hofors, Sweden .
    Ölund, P.
    Lugnet, A.
    Saffaripour, Mohsen
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Yang, Weihong
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Processer.
    Design optimization of flameless-oxyfuel soaking pit furnace using CFD technique2014Inngår i: Energy Procedia, 2014, Vol. 61, s. 611-614Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The effect of the combustion chamber’s configuration on the characteristics of flow and combustion parameters has been numerically investigated for a multi injecting, LPG, Flameless Oxy-fuel burner in a real-size soaking pit furnace, using CFD simulation. The simulation has been performed on two different furnace configurations, namely; small and large chambers of 15 m3 and 27 m3, with a height to width ratios of 1.49 and 2.02 respectively and with corresponding burner capacities of 560 kW and 900 kW. A major experimental trial has been performed in order to validate the results and reasonable consistency has been observed. The predicted results, with particular focus on the temperature distribution and heat transfer rate of two cases have been studied in detail.

  • 9.
    Ghalambaz, Mohammad
    et al.
    Ton Duc Thang University.
    Mansouri Mehryan, Seyed Abdollah
    Islamic Azad University, Yasooj.
    Ayoubi Ayoubloo, Kasra
    Shahid Chamran University of Ahvaz.
    El Kadri, Mohamad
    Université Ferhat Abbas Sétif-1; Centre Scientifique et Technique du Bâtiment.
    Hajjar, Ahmad
    Université de Lyon.
    Younis, Obai
    Department of Mechanical Engineering, College of Engineering at Wadi Addwaser, Prince Sattam Bin Abdulaziz University.
    Saffari Pour, Mohsen
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Hulme-Smith, Christopher
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Processer.
    Thermal Energy Storage and Heat Transfer of Nano-Enhanced Phase Change Material (NePCM) in a Shell and Tube Thermal Energy Storage (TES) Unit with a Partial Layer of Eccentric Copper Foam2021Inngår i: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 26, nr 5, artikkel-id 1491Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Thermal energy storage units conventionally have the drawback of slow charging response. Thus, heat transfer enhancement techniques are required to reduce charging time. Using nanoadditives is a promising approach to enhance the heat transfer and energy storage response time of materials that store heat by undergoing a reversible phase change, so-called phase change materials. In the present study, a combination of such materials enhanced with the addition of nanometer-scale graphene oxide particles (called nano-enhanced phase change materials) and a layer of a copper foam is proposed to improve the thermal performance of a shell-and-tube latent heat thermal energy storage (LHTES) unit filled with capric acid. Both graphene oxide and copper nanoparticles were tested as the nanometer-scale additives. A geometrically nonuniform layer of copper foam was placed over the hot tube inside the unit. The metal foam layer can improve heat transfer with an increase of the composite thermal conductivity. However, it suppressed the natural convection flows and could reduce heat transfer in the molten regions. Thus, a metal foam layer with a nonuniform shape can maximize thermal conductivity in conduction-dominant regions and minimize its adverse impacts on natural convection flows. The heat transfer was modeled using partial differential equations for conservations of momentum and heat. The finite element method was used to solve the partial differential equations. A backward differential formula was used to control the accuracy and convergence of the solution automatically. Mesh adaptation was applied to increase the mesh resolution at the interface between phases and improve the quality and stability of the solution. The impact of the eccentricity and porosity of the metal foam layer and the volume fraction of nanoparticles on the energy storage and the thermal performance of the LHTES unit was addressed. The layer of the metal foam notably improves the response time of the LHTES unit, and a 10% eccentricity of the porous layer toward the bottom improved the response time of the LHTES unit by 50%. The presence of nanoadditives could reduce the response time (melting time) of the LHTES unit by 12%, and copper nanoparticles were slightly better than graphene oxide particles in terms of heat transfer enhancement. The design parameters of the eccentricity, porosity, and volume fraction of nanoparticles had minimal impact on the thermal energy storage capacity of the LHTES unit, while their impact on the melting time (response time) was significant. Thus, a combination of the enhancement method could practically reduce the thermal charging time of an LHTES unit without a significant increase in its size.

    Fulltekst (pdf)
    fulltext
  • 10.
    Ghalambaz, Mohammad
    et al.
    Ton Duc Thang Univ, Metamat Mech Biomech & Multiphys Applicat Res Grp, Ho Chi Minh City, Vietnam.;Ton Duc Thang Univ, Fac Appl Sci, Ho Chi Minh City, Vietnam..
    Mehryan, S. A. M.
    Islamic Azad Univ, Yasooj Branch, Young Researchers & Elite Club, Yasuj, Iran..
    Mozaffari, Masoud
    Islamic Azad Univ, Dept Mech Engn, Najafabad Branch, Najafabad, Iran..
    Zadeh, Seyed Mohsen Hashem
    Shahid Chamran Univ Ahvaz, Dept Mech Engn, Ahwaz, Iran..
    Saffari Pour, Mohsen
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap. Shahid Bahonar Univ Kerman, Dept Mech Engn, Kerman, Iran..
    Study of thermal and hydrodynamic characteristics of water-nano-encapsulated phase change particles suspension in an annulus of a porous eccentric horizontal cylinder2020Inngår i: International Journal of Heat and Mass Transfer, ISSN 0017-9310, E-ISSN 1879-2189, Vol. 156, artikkel-id 119792Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this paper, the thermal and hydrodynamic characteristics of a suspension with water-Nano-Encapsulated Phase Change Material (NEPCM) in an annulus of a porous eccentric horizontal cylinder are investigated. The NEPCM particles have a core-shell structure and stability suspended in water. Hence, the particles, along with the liquid, could freely circulate inside the annuli of the horizontal cylinder due to the buoyancy forces. The cores of these particles are made from a Phase Change Material (PCM). Moreover, such cores are in a continuous exchange of heat transfer between the solid and liquid phases. The heat transfer is acting in a combination of absorption, storage, and release mechanisms. The governing equations for the fluid motions and conservation of energy could be written in partial differential forms and by using the appropriate non-dimensional variables converted into non-dimensional ones. Then, the numerical approach is applied by implementing the finite element method (FEM) to solve such equations iteratively. The impact of various non-dimensional parameters including the fusion temperature, Stefan number, Rayleigh number, Darcy number, the volume fraction of nanoparticles, and eccentricity of the inner cylinder is addressed on the flow and heat transfer. It is observed that the most favourable fusion temperature ranges for the maximum heat transfer rate vary as a function of the Rayleigh number. In addition, the heat transfer rate can be enhanced by applying the phase change core of nanoparticles.

  • 11.
    Ghalambaz, Mohammad
    et al.
    Ton Duc Thang University.
    Mehryan, Seyed Abdollah Mansouri
    Islamic Azad University.
    Hajjar, Ahmad
    Université de Lyon.
    Younis, Obai
    Prince Sattam Bin Abdulaziz University; University of Khartoum.
    Sheremet, Mikhail
    Tomsk State University.
    Saffari Pour, Mohsen
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Processer. Shahid Bahonar University of Kerman.
    Hulme-Smith, Christopher
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Processer.
    Phase-Transition Thermal Charging of a Channel-Shape Thermal Energy Storage Unit: Taguchi Optimization Approach and Copper Foam Inserts2021Inngår i: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 26, artikkel-id 1235Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Thermal energy storage is a technique that has the potential to contribute to future energy grids to reduce fluctuations in supply from renewable energy sources. The principle of energy storage is to drive an endothermic phase change when excess energy is available and to allow the phase change to reverse and release heat when energy demand exceeds supply. Unwanted charge leakage and low heat transfer rates can limit the effectiveness of the units, but both of these problems can be mitigated by incorporating a metal foam into the design of the storage unit. This study demonstrates the benefits of adding copper foam into a thermal energy storage unit based on capric acid enhanced by copper nanoparticles. The volume fraction of nanoparticles and the location and porosity of the foam were optimized using the Taguchi approach to minimize the charge leakage expected from simulations. Placing the foam layer at the bottom of the unit with the maximum possible height and minimum porosity led to the lowest charge time. The optimum concentration of nanoparticles was found to be 4 vol.%, while the maximu possible concentration was 6 vol.%. The use of an optimized design of the enclosure and the optimum fraction of nanoparticles led to a predicted charging time for the unit that was approximately 58% shorter than that of the worst design. A sensitivity analysis shows that the height of the foam layer and its porosity are the dominant variables, and the location of the porous layer and volume fraction of nanoparticles are of secondary importance. Therefore, a well-designed location and size of a metal foam layer could be used to improve the charging speed of thermal energy storage units significantly. In such designs, the porosity and the placement-location of the foam should be considered more strongly than other factors.

    Fulltekst (pdf)
    fulltext
  • 12.
    Kavian, Soheil
    et al.
    Sharif Univ Technol, Dept Mech Engn, RASES Lab, Tehran 79417, Iran..
    Saffari Pour, Mohsen
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik. Sharif Univ Technol, Dept Mech Engn, RASES Lab, Tehran 79417, Iran.
    Hakkaki-Fard, Ali
    Sharif Univ Technol, Dept Mech Engn, RASES Lab, Tehran 79417, Iran..
    Optimized Design of the District Heating System by Considering the Techno-Economic Aspects and Future Weather Projection2019Inngår i: Energies, E-ISSN 1996-1073, Vol. 12, nr 9, artikkel-id 1733Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    High mountains and cold climate in the north-west of Iran are critical factors for the design of optimized District Heating (DH) systems and energy-efficient buildings. It is essential to consider the Life Cycle Cost (LCC) that includes all costs, such as initial investment and operating costs, for designing an optimum DH system. Moreover, considering climate change for accurately predicting the required heating load is also necessary. In this research, a general optimization is carried out for the first time with the aim of a new design concept of a DH system according to a LCC, while considering all-involved parameters. This optimized design is based on various parameters such as ceiling and wall insulation thicknesses, depth of buried water and heating supply pipes, pipe insulation thickness, and boiler outlet temperature. In order to consider the future weather projection, the mentioned parameters are compared with and without climate change effects in a thirty-year period. The location selection was based on the potential of the region for such a system together with the harsh condition of the area to transport the common fossil fuel to the residential buildings. The obtained results show that insulation of walls is more thermally efficient than a roof with the same area in the selected case. In this case, polyurethane is the best material, which can cause a reduction of 59% in the heating load and, consequently, 2332 tons of CO2 emission annually. The most and the least investment payback periods are associated with the polyurethane and the glass wool insulation materials with the amounts of seven and one years. For the general optimization of the DH system, the Particle Swarm Optimization (PSO) method with a constriction coefficient was chosen. The results showed that the optimal thickness of the polyurethane layer for the thermal insulation of the building exterior walls is about 14 cm and the optimal outlet temperature of the boiler is about 95 degrees C. It can be also concluded that the optimal depth for the buried pipes is between 1.5 to 3 m underground. In addition, for the pipe with elastomeric insulation layer, the thickness of 2 cm is the optimal choice.

  • 13.
    Kazemi, Mania
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Saffari Pour, Mohsen
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Du, Sichen
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Experimental and Modelling Study on Reduction of Hematite Pellets by Hydrogen GasManuskript (preprint) (Annet vitenskapelig)
  • 14.
    Kazemi, Mania
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Saffari Pour, Mohsen
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Sichen, Du
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Experimental and Modeling Study on Reduction of Hematite Pellets by Hydrogen Gas2017Inngår i: Metallurgical and materials transactions. B, process metallurgy and materials processing science, ISSN 1073-5615, E-ISSN 1543-1916, Vol. 48, nr 2, s. 1114-1122Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Gaseous reduction by hydrogen was performed for three types of hematite pellets, two from industry and one prepared in the laboratory. The reduction mechanisms of the pellets were studied based on the morphologies of the partially reduced samples. Two mechanisms were found, the mechanisms of the two types of industrial pellets being very similar. The degree of reduction was followed as a function of time for each type of pellets. On the basis of the reaction mechanism of the industrial pellets, a mathematical model was developed. As a pioneer effort, the model combined the computational fluid dynamics approach for the flow and mass transfer in the gas phase with model of gas diffusion in the solid phase as well as the description of the chemical reaction at the reaction sites. The calculation results agreed well with the experimentally obtained reduction curves. The present work also emphasized the importance of evaluation of the reduction mechanisms and the properties of different types of iron ore pellets prior to developing a process model. While the present approach has established a good foundation for the dynamic modeling of the shaft reactor, more efforts are required to accomplish a realistic process model.

  • 15. Khodabandeh, E.
    et al.
    Akbari, O. A.
    Akbari, S.
    Taghizadeh, A.
    Saffari Pour, Mohsen
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik. KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad processmetallurgi.
    Ersson, Mikael
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    The effects of oil/MWCNT nanofluids and geometries on the solid oxide fuel cell cooling systems: a CFD study2020Inngår i: Journal of thermal analysis and calorimetry (Print), ISSN 1388-6150, E-ISSN 1588-2926Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this numerical study, the variations in the surface area of the cooling channels in a solid oxide fuel cell with different cross sections and multi-walled carbon nanotubes oil/MWCNT nanofluid volume fractions are considered. Rectangular, trapezoidal and elliptical cross sections, and nanofluid volume fractions of 0–6% for the fluid are chosen as the studied parameters as well as the mass flow rates. In this research, a 3D model is developed by the finite volume method using the computational fluid dynamics (CFD). Then, the flow field and the heat transfer rate are predicted. The results show that the dissipated heat in the fuel cell is dependent on the mass flow rate of the fluid. That increased heat increases the heat transfer rate. The presence of the solid particles can also reinforce the heat conduction of the coolant fluid and consequently improve the heat transfer performance. The pumping power is maximum for the highest mass flow rate and the highest solid nanoparticle volume fractions. Additionally, the pumping power is dependent on the route in which the sections with lowest momentum changes and lowest pressure drops have the least amount of the pumping power. The ratio of the dissipated heat by the nanofluid over the base fluid is compared to a pressure drop. The movement of flow with the lower mass flow rates will result in penetrations of the thermal boundary layers into different flow regions, which can increase the optimum temperature in the solid part of the fuel cell. By increasing the mass flow rate of the fluid passing through the channels from 0.002 to 0.004 kg s−1, the maximum temperature is decreased by 6.13, 3.34 and 6.35% for rectangular, trapezoidal and elliptical channels, respectively. 

  • 16. Khodabandeh, E.
    et al.
    Moghadasi, H.
    Saffari Pour, Mohsen
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik. KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad processmetallurgi.
    Ersson, Mikael
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Rosen, M. A.
    Rahbari, A.
    CFD study of non-premixed swirling burners: Effect of turbulence models2020Inngår i: Chinese Journal of Chemical Engineering, ISSN 1004-9541, E-ISSN 2210-321X, Vol. 28, nr 4, s. 1029-1038Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This research investigates a numerical simulation of swirling turbulent non-premixed combustion. The effects on the combustion characteristics are examined with three turbulence models: namely as the Reynolds stress model, spectral turbulence analysis and Re-Normalization Group. In addition, the P-1 and discrete ordinate (DO) models are used to simulate the radiative heat transfer in this model. The governing equations associated with the required boundary conditions are solved using the numerical model. The accuracy of this model is validated with the published experimental data and the comparison elucidates that there is a reasonable agreement between the obtained values from this model and the corresponding experimental quantities. Among different models proposed in this research, the Reynolds stress model with the Probability Density Function (PDF) approach is more accurate (nearly up to 50%) than other turbulent models for a swirling flow field. Regarding the effect of radiative heat transfer model, it is observed that the discrete ordinate model is more precise than the P-1 model in anticipating the experimental behavior. This model is able to simulate the subcritical nature of the isothermal flow as well as the size and shape of the internal recirculation induced by the swirl due to combustion. 

  • 17.
    Khodabandeh, Erfan
    et al.
    Amirkabir Univ Technol, Tehran Polytech, Mech Engn Dept, 424 Hafez Ave,POB 15875-4413, Tehran, Iran..
    Akbari, Omid Ali
    Islamic Azad Univ, Young Researchers & Elite Club, Khomeinishahr Branch, Khomeinishahr, Iran..
    Toghraie, Davood
    Islamic Azad Univ, Dept Mech Engn, Khomeinishahr Branch, Khomeinishahr 84175119, Iran..
    Saffari Pour, Mohsen
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processvetenskap. Sharif Univ Technol, Dept Mech Engn, Tehran, Iran..
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Ersson, Mikael
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
    Numerical investigation of thermal performance augmentation of nanofluid flow in microchannel heat sinks by using of novel nozzle structure: sinusoidal cavities and rectangular ribs2019Inngår i: Journal of the Brazilian Society of Mechanical Sciences and Engineering, ISSN 1678-5878, E-ISSN 1806-3691, Vol. 41, nr 10, artikkel-id UNSP 443Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this paper, we present a numerical simulation of a laminar, steady and Newtonian flow of f-graphene nanoplatelet/water nanofluid in a new microchannel design with factors for increasing heat transfer such as presence of ribs, curves to enable satisfactory fluid mixing and changing fluid course at the inlet and exit sections. The results of this study show that Nusselt number is dependent on nanoparticles concentration, inlet geometry and Reynolds number. As the nanofluid concentration increases from 0 to 0.1% and Reynolds number from 50 to 1000, the Nusselt number enhances nearly up to 3% for increase in fluid concentration and averagely from 15.45 to 54.1 and from 14.5 to 55.9 for geometry with and without rectangular rib, respectively. The presence of ribs in the middle section of microchannel and curves close to hot walls causes a complete mixing of the fluid in different zones. When the nanoparticles concentration is increased, the pressure drop and velocity gradient will become higher. An increased concentration of nanoparticles in contribution with higher Reynolds numbers only increases the fraction factor slightly. (The fraction factor increases nearly 37% and 35% for Re = 50 and 1000, respectively.) The highest uniform temperature distribution can be found in the first zones of fluid in the microchannel and by further movement of fluid toward exit section, because of decreasing difference between surface and fluid temperature, the growth of temperature boundary layer increases and results in non-uniformity in temperature distribution in microchannel and cooling fluid. With decrease in the concentration from 0 to 0.1%, the average outlet temperature and FOM decrease nearby 0.62% and 6.15, respectively.

  • 18.
    Liu, Hao
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik. Huazhong University of Science and Technology, China .
    Saffari Pour, Mohsen
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Mellin, Pelle
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Grip, C. -E
    Yang, Weihong
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Blasiak, Wlodzimierz
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    A thermodynamic study of hot syngas impurities in steel reheating furnaces: Corrosion and interaction with oxide scales2014Inngår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 77, s. 352-361Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Environmental concerns lead industries to implement gasified biomass (syngas) as a promising fuel in steel reheating furnaces. The impurities of syngas as well as a combination with iron oxide scale form complex mixtures with low melting points, and might cause corrosion on steel slabs. In this paper, the effects of syngas impurities are thermodynamically investigated, when scale formation on the steel slabs surface simultaneously takes place. A steel reheating furnace can be divided into preheating, heating, and soaking zones where the temperature of a steel slab changes respectively. Therefore, the thermodynamic calculation is performed at different temperatures to predict the fate of impurities. Then, the stable species are connected with respective zones in a reheating furnace. It is concluded that reactions due to alkali compounds, chloride, and particulate matter could take place on steel slabs. In the low temperature range, interaction of sodium chloride occured with pure iron prior to scale formation. Then, at high temperature the reactions of impurities are notable with iron oxides due to scale growing. Furthermore, the multicomponent reactions with syngas impurities showed that most of alkali contents evaporate at first stages, and only small amounts of them remain in slag at high temperature.

  • 19. Momeni Dolatabadi, Amir
    et al.
    Saffari Pour, Mohsen
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Mousavi Ajarostaghi, Seyed Soheil
    Poncet, Sébastien
    Hulme-Smith, Christopher
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Processer.
    Last stage stator blade profile improvement for a steam turbine under a non-equilibrium condensation condition: A CFD and cost-saving approach2023Inngår i: Alexandria Engineering Journal, ISSN 1110-0168, E-ISSN 2090-2670, Vol. 73, s. 27-46Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Non-equilibrium phenomena and related damages have always been one of the great concerns among researchers, designers, and industry managers. In power plants, the overhaul of turbines during a pre-planned schedule includes checking, repairing, and replacing damaged parts, which always challenge industry investors with variable costs. In this study, a modified profile for the stationary cascade blades of a 200 MW steam turbine is predicted by help of the Computational Fluid Dynamics (CFD) according to a cost-saving approach for a power plant. Wet steam model is used to investigate the flow behavior between the turbine blades, due to the sonication and non-equilibrium phenomena. The numerical model based on the Eulerian-Eulerian approach accounts the turbulence caused by the presence of droplets, condensation shocks and aerodynamics. At first, such model has been carefully validated against the available experimental data. Then, the entrance edge of the blade is designed considering different shapes and sizes. The flow behavior at the entrance edge region has been fully investigated. Finally, according to the criteria for measuring the non-equilibrium flow phenomena (erosion rate, Mach number, entropy, exergy destruction and transfer of mass and heat between flow phases), a modified model for the steam turbine blade considering the economic aspects has been presented. The modified blade model exhibits 88%, 0.13% and 7% reduction in the erosion rate, entropy generation and exergy destruction, respectively. Furthermore, the application of this modified blade profile save 456$ of the total monthly maintenance costs.

    Fulltekst (pdf)
    fulltext
  • 20. Sabzpoushan, S.
    et al.
    Jafari Mosleh, H.
    Kavian, S.
    Saffari Pour, Mohsen
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Mohammadi, O.
    Aghanajafi, C.
    Ahmadi, M. H.
    Nonisothermal two-phase modeling of the effect of linear nonuniform catalyst layer on polymer electrolyte membrane fuel cell performance2020Inngår i: Energy Science & Engineering, ISSN 2050-0505, Vol. 8, nr 10, s. 3575-3587Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this research, it is investigated to numerically evaluate the performance of a polymer electrolyte membrane fuel cell (PEMFC). The performance is investigated through the nonuniformity gradient loading at the catalyst layer (CL) of the considered PEMFC. Computational fluid dynamics is used to simulate a 2D domain in which a steady-state laminar compressible flow in two-phase for the PEMFC has been considered. In this case, a particular nonuniform variation inside the CL along the channel is assumed. The nonuniform gradient is created using a nonisothermal domain to predict the flooding effects on the performance of the PEMFC. The computational domain is considered as the cathode of PEMFC, which is divided into three regions: a gas channel, a gas diffusion layer, and a CL. The loading variation inside the catalyst is defined as a constant slope along the channel. In order to find the optimum slope, different slope angles are analyzed. The results point out that the nonuniform loading distribution of the catalyst (platinum) along the channel could improve the fuel cell performance up to 1.6% and 5% for power density and voltage generation, respectively. It is inferred that it is better to use more catalyst in the final section of the channel if the performance is the main concern.

  • 21.
    Sadat, Elaheh Sadat
    et al.
    Amirkabir Univ Technol, Elect Engn Dept, Tehran 158754413, Iran.
    Faez, Karim
    Amirkabir Univ Technol, Elect Engn Dept, Tehran 158754413, Iran.
    Saffari Pour, Mohsen
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik. KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad processmetallurgi. Sharif Univ Technol, Dept Mech Engn, Tehran 1458889694, Iran.
    Entropy-Based Video Steganalysis of Motion Vectors2018Inngår i: Entropy, E-ISSN 1099-4300, Vol. 20, nr 4, artikkel-id 244Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this paper, a new method is proposed for motion vector steganalysis using the entropy value and its combination with the features of the optimized motion vector. In this method, the entropy of blocks is calculated to determine their texture and the precision of their motion vectors. Then, by using a fuzzy cluster, the blocks are clustered into the blocks with high and low texture, while the membership function of each block to a high texture class indicates the texture of that block. These membership functions are used to weight the effective features that are extracted by reconstructing the motion estimation equations. Characteristics of the results indicate that the use of entropy and the irregularity of each block increases the precision of the final video classification into cover and stego classes.

  • 22.
    Saffari Pour, Mohsen
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Producer Gas Implementation in Steel Reheating Furnaces from Lab to Industrial Scale: A Computational Fluid Dynamics and Thermodynamics Approach2016Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The integrated steel-making plants in Sweden contributed with approximately 8 % of the total CO2 emissions in the country in 2011. A major contributor to these emissions is the combustion of fossil fuels in different process units. Therefore, it is essential to reduce emissions by limiting the fossil fuels consumption in the steel industry. A possible solution to reduce the emissions is to implement alternative fuels, which are produced from various combustion and gasification sectors in the iron and steel-making industry. Currently, the blast furnace gas (BFG) and coke oven gas (COG) are extensively used for district heating purposes. Depending on the availability of biomass in a region, gasified biomass (Syngas) can also be used as an alternative fuel source. In addition, the extracted energy from these producer gases can be used in other heat treatment processes such as reheating furnaces. However, these producer gases contain several impurities such as, alkali metals, halogens, particulate matter, sulfur compounds and other mineral contaminants, which can be problematic. For instance, in the steel reheating furnaces, these impurities can form sticky layers of solutions on the steel slab surfaces which are not easy to remove.

                The High Temperature Agent Combustion (HiTAC) technology has several advantages compared to the conventional methods. These include temperature uniformity, a flexibility of fuels, low pollutant emissions and a volumetric combustion. In this study, these factors have been investigated for the pulverized coal combustion, when the coal particles are assumed to follow a Rosin-Rammler distribution. Moreover, due to the mentioned superior properties of HiTAC technique, it has also been applied for the combustion of producer gases as alternative fuel for steel reheating furnaces.

                A coupled Computational Fluid Dynamics (CFD) and thermodynamics approach has been developed to analyze the combustion of producer gases and the behavior of impurities in these gases for the steel reheating furnaces. The obtained results prove the capability of HiTAC technique to be used for the combustion of producer gases by enhancing the temperature and by reducing the size of steel reheating furnaces. The findings also show that the Low Calorific Value (LCV) of BFG and the presence of 52 % nitrogen in the gas are responsible for a lower heat release in comparison to other producer gases.

                The impurities in steel reheating furnaces are considered as ash particles having a particle size distribution similar to the pulverized coal particles. The accumulation of the ash particles at the steel slab surface is predicted using the CFD simulations. Furthermore, the thermo-chemical calculations are used to understand the effect of all the involved chemical compositions in an equilibrium thermodynamics system of impurities and iron-oxides. This thermodynamics study of impurities is divided in two steps. In the first study, at the steel slab surface, the temperature gradients and the concentration of impurities are not considered. This investigation is carried out to identify the reactivity and phase transformation of different ash mineral components with respect to the temperature zones (preheating, heating and soaking) in steel reheating furnaces. Here, chloride compounds are the most reactive compounds in comparison to other impurities. It is also found that an increased temperature from the preheating zone up to the soaking zone leads to an increased iron-oxide formation. In the heating and soaking zones, an addition of mineral compounds like SiO2 and CaO is also found to accelerate the formation of the sticky solutions at the steel slab surface. Moreover, by increasing the steel slab temperature the formations of sticky layers are highly abated in the late heating zone and the entire soaking zones.

                In the second study the concentration of particles, density of particles and temperature gradients at the steel slab surface are taken into account. Thereby, the shortcomings of the first thermodynamics system are improved. It is found that for the considered furnace configuration, the particles received the same velocity as the injected fuel (70 m/s) and they are heated up to a temperature of 1600 °C. The most of the particles, with the average size of 50 µm, are evacuated through the exhaust ports due to the inertial dominant force. Only around 10 percent of these particles have a tendency to stick to the steel slab surface at the heating zone rather than at the soaking zone. These findings could be applied for improvements in the combustion systems and furnace designs to reduce unwanted accumulations and hot-spots of sticky layers on the steel slab surface. This information may also be useful for planning of new investments in gas cleaning systems, if producer gases are used as fuels.

  • 23.
    Saffari Pour, Mohsen
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Andersson, Nils
    Ersson, Mikael
    Jonsson, Lage Tord Ingemar
    Jönsson, Pär Göran
    On Thermochemical Behaviors of Ash Particles during Combustion of Producer Gases inside a Steel Reheating FurnaceManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    The use of producer gases from gasification and combustion of fossil fuels and biofuels in steel reheating furnaces represents a promising future application. Prior to the direct implementation of such gases as an alternative fuel for high quality steel products, a comprehensive thermochemical study of possible impurities inside the furnace is crucial. This is especially important for heating of high quality steel products. Ash is one of these impurities, which contains particular compounds like Sodium (Na), Potassium (K), Chloride (Cl), and other minerals. The depositions of these compounds, which cause a formation of sticky layer of solutions on the steel slabs surface, are responsible for low quality products. Furthermore, it is a challenge and energy consuming process to remove these elements from the slabs. In this paper, the combustion of a producer gas mixture including ash particles inside a batch type steel reheating furnace has been investigated. In the first step, a computational fluid dynamics (CFD) approach is utilized to investigate the feasible locations of ash particles at the interface layer of the flaring gas media and the steel slab surface. After that, result from thermodynamic calculations considering the slab temperature, particle concentrations, ash compositions, and its reactions with the steel slab are presented. The results show that the concentration of particles is highly dependent on the flow field, slab temperature, as well as their size distribution. Also, the most probable places of particles at the interface layer of flaring gas media and the steel slab surface is primarily found near the steel slab cross sectional sides in the heating zone. It is believed that the present results could be helpful for a further optimization of furnace and combustion system design.

  • 24.
    Saffari Pour, Mohsen
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Andersson, Nils Å. I.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Ersson, Mikael
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Jonsson, Lage Tord Ingemar
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Niska, John
    Rensgard, Anders
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    The Behavior of Impurities During Producer Gas Implementation as Alternative Fuel in Steel Reheating Furnaces: A CFD and Thermo-Chemical Study2016Inngår i: ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), USA: The American Society of Mechanical Engineers , 2016, Vol. 6A, artikkel-id V06AT08A011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The use of available and cheap industrial producer gases as alternative fuels for the steel reheating furnaces is an attractive topic for steel industry. The application of producer gases for such furnaces introduces not only the complicated combustion system of Low Calorific Value (LCV) gases, but also several impurities that could be problematic for the quality of final steel products. The quality of steel can be highly affected by the interaction of impurities with iron-oxides at hot slab surfaces. In this research, the combustion of producer gases and the behavior of impurities at the steel slab surface are studied by aid of a novel coupled computational fluid dynamics (CFD) and thermodynamics approach. The impurities are introduced as mineral ash particles with the particle size distributions of 15–100 μm. The CFD predicted data regarding the accumulation of ash particles are extracted from an interface layer at the flaring gas media around the steel slab surface. Later on, these predicted data are used for the thermo-chemical calculations regarding the formation of sticky solutions and stable phases at the steel slab surface. The results show that the particles are more likely follow the flow due to the high injection velocity of fuel (70 m/s) and the dominant inertial forces. More than 90 percent of particles have been evacuated through the exhaust pipes. The only 10 percent of remaining particles due to the high recirculation zones at the middle of furnace and the impinging effect of front walls tend to stick to the side wall of slab in the heating zone more than the soaking zone.

  • 25.
    Saffari Pour, Mohsen
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Ersson, Mikael
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Jonsson, Lage Tord Ingemar
    Andersson, Nils
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Saffaripour, Mohammadhassan
    Shahid Bahonar University of Kerman, Kerman, Iran.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    On the Implementation of Producer Gases as Alternative Fuels in Steel Reheating Furnaces2015Inngår i: Proccedings of ASME 2015 International Mechanical Engineering Congress and Exposition / [ed] ASME, Houston, Texas, USA, November 13–19, 2015: ASME Press, 2015, Vol. 6AKonferansepaper (Fagfellevurdert)
    Abstract [en]

    During the past decades, combustion of producer gases from other facilities has been introduced as one of the promising techniques in steel furnaces. The impurities inside producer gases are responsible for a low quality steel production due to formation of the molten ash that forms sticky layers of solutions on steel surfaces. Therefore, a comprehensive investigation is needed before a full implementation of producer gases inside the industrial furnaces. In this paper, the effects of impurities inside the gasified biomass flue gases are thermodynamically investigated regarding temperature zones inside a reheating furnace. After that, the high temperature agent combustion (HiTAC) is investigated as a solution for a steel batch reheating furnace to reduce the side effects of using the producer gases. Finally, computational fluid dynamics (CFD) is used as a numerical technique to compare four different producer gases in the studied furnace. The temperature distribution is validated with existing literature data. It shows a good agreement with a 5% error in the heating and a 10% error in the soaking zones of the reheating furnace. The comparison of simulation results assists in the understanding of the chemical and thermal behavior of different gases and provides useful data for the furnace fuel optimization.

  • 26.
    Saffari Pour, Mohsen
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik. Sharif Univ Technol, Dept Mech Engn, Tehran 79417, Iran..
    Hakkaki-Fard, Ali
    Sharif Univ Technol, Dept Mech Engn, Tehran 79417, Iran..
    Firoozabadi, Bahar
    Sharif Univ Technol, Dept Mech Engn, Tehran 79417, Iran..
    Numerical Investigation of a Portable Incinerator: A Parametric Study2020Inngår i: Processes, ISSN 2227-9717, Vol. 8, nr 8, artikkel-id 923Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The application of incinerators for the municipal solid waste (MSW) is growing due to the ability of such instruments to produce energy and, more specifically, reduce waste volume. In this paper, a numerical simulation of the combustion process with the help of the computational fluid dynamics (CFD) inside a portable (mobile) incinerator has been proposed. Such work is done to investigate the most critical parameters for a reliable design of a domestic portable incinerator, which is suitable for the Iranian food and waste culture. An old design of a simple incinerator has been used to apply the natural gas (NG), one of the available cheap fossil fuels in Iran. After that, the waste height, place of the primary burner, and the flow rate of the cooling air inside the incinerator, as the main parameters of the design, are investigated. A validation is also performed for the mesh quality test and the occurrence of the chemical reactions near the burner of the incinerator. Results proved that the numerical results have less than 5% error compared to the previous experimental and numerical approaches. In addition, results show that by moving the primary burner into the secondary chamber of the incinerator, the temperature and the heating ability of the incinerator could be affected dramatically. Moreover, it has been found that by increasing the flow rate of the cooling air inside the incinerator to some extent, the combustion process is improved and, on the other hand, by introducing more cooling air, the evacuation of the hazardous gases from the exhaust is also improved.

  • 27. Saffari Pour, Mohsen
    et al.
    Mellin, Pelle
    Yang, Weihong
    Blasiak, Wlodzimierz
    Numerical Investigation of Syngas Combustion in a HiTAG System Using CFD Techniques2014Inngår i: PROCEEDINGS of the 10th International Conference on Computational Fluid Dynamics in the Oil & Gas, Metallurgical and Process Industries / [ed] Stein Tore Johansen & Jan Erik Olsen, Trondheim, 2014Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Utilization of gasified biomass in the case of combustion could introduce a prominent way to high energy efficiency, pollutant emissions reduction, and heat recovery purposes. In this paper, secondary syngas combustion chamber of high temperature agent gasification (HiTAG) system is modelled with computational fluid dynamics (CFD) techniques. The numerical data in terms of temperature distribution and flue gas concentrations are compared with experimental measurements through the whole volume of such chamber. In order to reduce the pollutant emissions, and more efficient volumetric combustion, a low NOX burner is used in the secondary chamber. The validation of numerical results with experimental measurements shows a good consistency through the entire chamber. It is concluded that the NOX emission due to secondary air injection, and low NOX burner decreased significantly prior to spread in atmosphere. Moreover, the concentration of oxygen and carbon monoxide at the combustion exhaust reveals a reliable combustion system.

  • 28.
    Saffari Pour, Mohsen
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Yang, Weihong
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Performance of pulverized coal combustion under high temperature air diluted by steam2014Inngår i: ISRN Mechanical Engineering, ISSN 2090-5122, E-ISSN 2090-5130, Vol. 2014Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The high temperature air combustion (HiTAC) is an advanced promising technology for heat recovery, energy saving, and stability improvement of flame. Computational fluid dynamic (CFD) is known as an applied tool to execute HiTAC modeling. In this paper, performances of pulverized coal combustion under the high preheated and oxygen deficient air are studied by both experimental and numerical methodology. The experimental facilities have been accomplished in a HiTAC chamber with coal injection velocity that ranges from 10 to 40 m/s. In order to achieve different preheated temperatures, the combustion air in such system is diluted by variable steam percentages from 0 to 44%. Results of mathematical simulation and experimental tests present convincible agreement through whole region. It is concluded that NOX emission is reduced by increasing the steam percentage in the oxidizer due to decreasing the flame temperature. Besides, graphical contours show that by adding more steam to oxidizer composition, the oxygen concentration decreased. Additionally, results show that when the injection speed of fuel is increased, NOX emission is also increased, and when the injection rate of preheated air is increased, NOX emission shows decreasing trend. Further contribution in future is needed to investigate the performance of such technologies.

  • 29.
    Svidró, Péter
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap. Jönköping University.
    Diószegi, Attila
    Jönköping University.
    Saffari Pour, Mohsen
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Investigation of Dendrite Coarsening in Complex Shaped Lamellar Graphite Iron Castings2017Inngår i: Metals, ISSN 2075-4701, Vol. 7, s. 244-Artikkel i tidsskrift (Fagfellevurdert)
    Fulltekst (pdf)
    fulltext
  • 30.
    Valizadeh, Reza
    et al.
    Sharif University of Technology.
    Abbaspour, Madjid
    Sharif University of Technology.
    Rahni, Mohammad Taeibi
    Sharif University of Technology.
    Saffari Pour, Mohsen
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap. Shahid Bahonar University of Kerman.
    Hulme-Smith, Christopher
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Processer.
    Improved Wells Turbine using a Concave Sectional ProfileManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    The current need to develop sustainable power sources has led to the development of ocean-based conversion systems. Wells turbine is a widely used converter in such systems which suffers from a lack of operational range and power production capacity under operational conditions. The profile named IFS which is concave in the post-mid-chord region, can produce significantly larger lift forces and show better separation behavior than the NACA profiles. In the present study, we tested this profile for the first time in a Wells turbine. The performance of six different blade designs with IFS and NACA profiles were evaluated and compared using a validated computational fluid dynamic model. Although the substitution of the NACA profile with the IFS profile in all cases increased the torque generated, the most efficient power generation and the largest efficient range were achieved in the design with varying thickness from the hub with a 0.15 thickness ratio reaching to the ratio of 0.2 at the tip. The operational span of this design with the IFS profile was 24.1% greater and the maximum torque generation was 71% higher than the case with the NACA profile. Therefore, the use of the IFS profile is suggested for further study and practical trials.

    Fulltekst (pdf)
    fulltext
  • 31.
    Zadeh, Seyed Mohsen Hashem
    et al.
    Shahid Chamran Univ, Dept Mech Engn, Ahwaz 61355, Iran..
    Heidarshenas, Mohammadhosein
    Shahid Chamran Univ, Dept Mech Engn, Ahwaz 61355, Iran..
    Ghalambaz, Mohammad
    Ton Duc Thang Univ, Metama Mech Biomech & Multiphys Applicat Res Grp, Ho Chi Minh City 758307, Vietnam.;Ton Duc Thang Univ, Fac Appl Sci, Ho Chi Minh City 758307, Vietnam..
    Noghrehabadi, Aminreza
    Shahid Chamran Univ, Dept Mech Engn, Ahwaz 61355, Iran..
    Saffari Pour, Mohsen
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik. KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad processmetallurgi.
    Numerical Modeling and Investigation of Amperometric Biosensors with Perforated Membranes2020Inngår i: Sensors, E-ISSN 1424-8220, Vol. 20, nr 10Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The present paper aims to investigate the influence of perforated membrane geometry on the performance of biosensors. For this purpose, a 2-D axisymmetric model of an amperometric biosensor is analyzed. The governing equations describing the reaction-diffusion equations containing a nonlinear term related to the Michaelis-Menten kinetics of the enzymatic reaction are introduced. The partial differential governing equations, along with the boundary conditions, are first non-dimensionalized by using appropriate dimensionless variables and then solved in a non-uniform unstructured grid by employing the Galerkin Finite Element Method. To examine the impact of the hole-geometry of the perforated membrane, seven different geometries-including cylindrical, upward circular cone, downward circular cone, upward paraboloid, downward paraboloid, upward concave paraboloid, and downward concave paraboloid-are studied. Moreover, the effects of the perforation level of the perforated membrane, the filling level of the enzyme on the transient and steady-state current of the biosensor, and the half-time response are presented. The results of the simulations show that the transient and steady-state current of the biosensor are affected by the geometry dramatically. Thus, the sensitivity of the biosensor can be influenced by different hole-geometries. The minimum and maximum output current can be obtained from the cylindrical and upward concave paraboloid holes. On the other hand, the least half-time response of the biosensor can be obtained in the cylindrical geometry.

  • 32.
    Zeraatpisheh, Milad
    et al.
    Sharif Univ Technol, Dept Mech Engn, Tehran 79417, Iran..
    Arababadi, Reza
    Grad Univ Adv Technol, Inst Sci & High Technol & Environm Sci, Dept Energy, Kerman 76169, Iran..
    Pour, Mohsen Saffari
    KTH.
    Economic Analysis for Residential Solar PV Systems Based on Different Demand Charge Tariffs2018Inngår i: Energies, E-ISSN 1996-1073, Vol. 11, nr 12, artikkel-id 3271Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    It is well known that the use of photovoltaic (PV) systems helps to preserve the environment, produce lower levels of greenhouse gases (GHGs), and reduce global warming, however, whether it is economically profitable for customers or not is highly debatable. This paper aims to address this issue. To be comprehensive, three different types of buildings are considered as case studies. Then, these three buildings are modeled in EnergyPlus to determine the rate of energy consumption. Afterward, comparisons of various solar system sizes based on economic parameters such as the internal rate of return, the net present value, payback period and profitability indexing for various-sized PV systems are carried out. The results show that by the demand charge tariffs, using PV systems has no economic justification. It has been shown that even with neglecting further costs of the PV system like maintenance, by demand charge tariffs, it is not economically beneficial for customers to use the PV systems. Profitability index of all three buildings with various PV power systems is between 0.2 to 0.8, which are by no means is desirable. Moreover, it was found that bigger solar systems are less cost-effective in the presence of demand charges.

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