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Saffari Pour, MohsenORCID iD iconorcid.org/0000-0002-5976-2697
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Publications (10 of 31) Show all publications
Momeni Dolatabadi, A., Saffari Pour, M., Mousavi Ajarostaghi, S. S., Poncet, S. & Hulme-Smith, C. (2023). Last stage stator blade profile improvement for a steam turbine under a non-equilibrium condensation condition: A CFD and cost-saving approach. Alexandria Engineering Journal, 73, 27-46
Open this publication in new window or tab >>Last stage stator blade profile improvement for a steam turbine under a non-equilibrium condensation condition: A CFD and cost-saving approach
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2023 (English)In: Alexandria Engineering Journal, ISSN 1110-0168, E-ISSN 2090-2670, Vol. 73, p. 27-46Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Elsevier BV, 2023
Keywords
Steam turbine, Modified blade profile, Non-equilibrium condensation, Economical analysis, CFD
National Category
Energy Engineering
Research subject
Energy Technology; Applied and Computational Mathematics
Identifiers
urn:nbn:se:kth:diva-328188 (URN)10.1016/j.aej.2023.04.011 (DOI)000990332300001 ()2-s2.0-85153573888 (Scopus ID)
Note

QC 20230613

Available from: 2023-06-05 Created: 2023-06-05 Last updated: 2023-06-13Bibliographically approved
Ghalambaz, M., Mehryan, S. A., Hajjar, A., Younis, O., Sheremet, M., Saffari Pour, M. & Hulme-Smith, C. (2021). Phase-Transition Thermal Charging of a Channel-Shape Thermal Energy Storage Unit: Taguchi Optimization Approach and Copper Foam Inserts. Molecules, 26, Article ID 1235.
Open this publication in new window or tab >>Phase-Transition Thermal Charging of a Channel-Shape Thermal Energy Storage Unit: Taguchi Optimization Approach and Copper Foam Inserts
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2021 (English)In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 26, article id 1235Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
MDPI AG, 2021
Keywords
thermal energy storage; copper foam; phase transition; fast charging
National Category
Energy Engineering
Research subject
Energy Technology; Materials Science and Engineering
Identifiers
urn:nbn:se:kth:diva-293864 (URN)10.3390/molecules26051235 (DOI)000628423100001 ()33669098 (PubMedID)2-s2.0-85102697158 (Scopus ID)
Note

QC 20210710

Available from: 2021-05-03 Created: 2021-05-03 Last updated: 2023-08-28Bibliographically approved
Ghalambaz, M., Mansouri Mehryan, S. A., Ayoubi Ayoubloo, K., El Kadri, M., Hajjar, A., Younis, O., . . . Hulme-Smith, C. (2021). 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 Foam. Molecules, 26(5), Article ID 1491.
Open this publication in new window or tab >>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 Foam
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2021 (English)In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 26, no 5, article id 1491Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Basel, Switzerland: , 2021
Keywords
latent heat thermal energy storage; annuli enclosure; graphene oxide nanoparticles; copper metal foam; thermal enhancement
National Category
Other Materials Engineering Other Chemical Engineering
Research subject
Materials Science and Engineering
Identifiers
urn:nbn:se:kth:diva-301149 (URN)10.3390/molecules26051491 (DOI)000628437000001 ()33803388 (PubMedID)2-s2.0-85103862773 (Scopus ID)
Note

QC 20210907

Available from: 2021-09-05 Created: 2021-09-05 Last updated: 2023-08-28Bibliographically approved
Khodabandeh, E., Moghadasi, H., Saffari Pour, M., Ersson, M., Jönsson, P., Rosen, M. A. & Rahbari, A. (2020). CFD study of non-premixed swirling burners: Effect of turbulence models. Chinese Journal of Chemical Engineering, 28(4), 1029-1038
Open this publication in new window or tab >>CFD study of non-premixed swirling burners: Effect of turbulence models
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2020 (English)In: Chinese Journal of Chemical Engineering, ISSN 1004-9541, E-ISSN 2210-321X, Vol. 28, no 4, p. 1029-1038Article in journal (Refereed) Published
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. 

Place, publisher, year, edition, pages
Elsevier BV, 2020
Keywords
Computational Fluid Dynamics (CFD), Large eddy simulations, Modeling validation, Non-premixed flames, Radiative heat transfer model, Turbulent combustion
National Category
Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-274035 (URN)10.1016/j.cjche.2020.02.016 (DOI)000555483300009 ()2-s2.0-85082007381 (Scopus ID)
Note

QC 20200630

Available from: 2020-06-30 Created: 2020-06-30 Last updated: 2022-06-26Bibliographically approved
Alsabery, A. I., Hashim, I., Hajjar, A., Ghalambaz, M., Nadeem, S. & Saffari Pour, M. (2020). Entropy Generation and Natural Convection Flow of Hybrid Nanofluids in a Partially Divided Wavy Cavity Including Solid Blocks. Energies, 13(11), Article ID 2942.
Open this publication in new window or tab >>Entropy Generation and Natural Convection Flow of Hybrid Nanofluids in a Partially Divided Wavy Cavity Including Solid Blocks
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2020 (English)In: Energies, E-ISSN 1996-1073, Vol. 13, no 11, article id 2942Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
MDPI AG, 2020
Keywords
complex wavy wall cavity, entropy generation, natural convection, hybrid nanofluid, solid blocks, finite element method
National Category
Energy Engineering
Identifiers
urn:nbn:se:kth:diva-278808 (URN)10.3390/en13112942 (DOI)000545401100269 ()2-s2.0-85088385536 (Scopus ID)
Note

QC 20200728

Available from: 2020-07-28 Created: 2020-07-28 Last updated: 2023-08-28Bibliographically approved
Arjmandi, H., Amiri, P. & Saffari Pour, M. (2020). Geometric optimization of a double pipe heat exchanger with combined vortex generator and twisted tape: A CFD and response surface methodology (RSM) study. Thermal Science and Engineering Progress, 18, Article ID 100514.
Open this publication in new window or tab >>Geometric optimization of a double pipe heat exchanger with combined vortex generator and twisted tape: A CFD and response surface methodology (RSM) study
2020 (English)In: Thermal Science and Engineering Progress, ISSN 2451-9049, Vol. 18, article id 100514Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Central composite design (CCD) technique, Combined vortex generator and twisted tape turbulator, Double pipe heat exchanger, Pressure drop, Response surface methodology (RSM)
National Category
Mechanical Engineering
Identifiers
urn:nbn:se:kth:diva-276310 (URN)10.1016/j.tsep.2020.100514 (DOI)000621593000015 ()2-s2.0-85083169381 (Scopus ID)
Note

QC 20200617

Available from: 2020-06-17 Created: 2020-06-17 Last updated: 2022-06-26Bibliographically approved
Sabzpoushan, S., Jafari Mosleh, H., Kavian, S., Saffari Pour, M., Mohammadi, O., Aghanajafi, C. & Ahmadi, M. H. (2020). Nonisothermal two-phase modeling of the effect of linear nonuniform catalyst layer on polymer electrolyte membrane fuel cell performance. Energy Science & Engineering, 8(10), 3575-3587
Open this publication in new window or tab >>Nonisothermal two-phase modeling of the effect of linear nonuniform catalyst layer on polymer electrolyte membrane fuel cell performance
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2020 (English)In: Energy Science & Engineering, ISSN 2050-0505, Vol. 8, no 10, p. 3575-3587Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
John Wiley and Sons Ltd, 2020
Keywords
computational fluid dynamics, gas diffusion, nonuniform catalyst layer, polymer electrolyte membrane fuel cell, two-phase flow, Catalysts, Diffusion in gases, Polyelectrolytes, Proton exchange membrane fuel cells (PEMFC), Two phase flow, Computational domains, Different slopes, Fuel cell performance, Gas diffusion layers, Non-uniform catalysts, Nonuniform loadings, Polymer electrolyte membranes, Voltage generations, Solid electrolytes
National Category
Energy Engineering
Identifiers
urn:nbn:se:kth:diva-286566 (URN)10.1002/ese3.765 (DOI)000540653300001 ()2-s2.0-85086512364 (Scopus ID)
Note

QC 20201210

Available from: 2020-12-10 Created: 2020-12-10 Last updated: 2022-06-25Bibliographically approved
Saffari Pour, M., Hakkaki-Fard, A. & Firoozabadi, B. (2020). Numerical Investigation of a Portable Incinerator: A Parametric Study. Processes, 8(8), Article ID 923.
Open this publication in new window or tab >>Numerical Investigation of a Portable Incinerator: A Parametric Study
2020 (English)In: Processes, ISSN 2227-9717, Vol. 8, no 8, article id 923Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
MDPI AG, 2020
Keywords
portable incinerator, computational fluid dynamics (CFD), combustion, parametric study
National Category
Energy Engineering
Identifiers
urn:nbn:se:kth:diva-282253 (URN)10.3390/pr8080923 (DOI)000567081800001 ()2-s2.0-85089739220 (Scopus ID)
Note

QC 20201103

Available from: 2020-11-03 Created: 2020-11-03 Last updated: 2022-06-25Bibliographically approved
Zadeh, S. M., Heidarshenas, M., Ghalambaz, M., Noghrehabadi, A. & Saffari Pour, M. (2020). Numerical Modeling and Investigation of Amperometric Biosensors with Perforated Membranes. Sensors, 20(10)
Open this publication in new window or tab >>Numerical Modeling and Investigation of Amperometric Biosensors with Perforated Membranes
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2020 (English)In: Sensors, E-ISSN 1424-8220, Vol. 20, no 10Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
MDPI, 2020
Keywords
amperometric biosensor, biosensor current, finite element method, half-time response, mathematical model
National Category
Computational Mathematics
Identifiers
urn:nbn:se:kth:diva-277703 (URN)10.3390/s20102910 (DOI)000539323700164 ()32455593 (PubMedID)2-s2.0-85085274709 (Scopus ID)
Note

QC 20200629

Available from: 2020-06-29 Created: 2020-06-29 Last updated: 2022-06-26Bibliographically approved
Alsabery, A. I., Ghalambaz, M., Armaghani, T., Chamkha, A., Hashim, I. & Saffari Pour, M. (2020). Role of Rotating Cylinder toward Mixed Convection inside a Wavy Heated Cavity via Two-Phase Nanofluid Concept. Nanomaterials, 10(6), Article ID 1138.
Open this publication in new window or tab >>Role of Rotating Cylinder toward Mixed Convection inside a Wavy Heated Cavity via Two-Phase Nanofluid Concept
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2020 (English)In: Nanomaterials, E-ISSN 2079-4991, Vol. 10, no 6, article id 1138Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
MDPI, 2020
Keywords
mixed convection, thermophoresis and Brownian motion, wavy cavity, two-phase nanofluid concept, wavy heater, rotating circular cylinder
National Category
Energy Engineering
Identifiers
urn:nbn:se:kth:diva-279218 (URN)10.3390/nano10061138 (DOI)000554765300001 ()32526982 (PubMedID)2-s2.0-85088780602 (Scopus ID)
Note

QC 20200818

Available from: 2020-08-18 Created: 2020-08-18 Last updated: 2022-06-26Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-5976-2697

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