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Publications (10 of 39) Show all publications
Thantla, S., Aspfors, J., Fridh, J. & Christiansen Erlandsson, A. (2019). Characterization of an organic Rankine cycle system for waste heat recovery from heavy-duty engine coolant and exhaust. In: : . Paper presented at 5th International symposium on ORC power systems, 9 – 11 September 2019, Athens. , Article ID 159.
Open this publication in new window or tab >>Characterization of an organic Rankine cycle system for waste heat recovery from heavy-duty engine coolant and exhaust
2019 (English)Conference paper, Published paper (Other academic)
Abstract [en]

To meet the strict legislations imposed on carbon-dioxide emissions, organic Rankine cycle (ORC) waste heat recovery (WHR) technology is being extensively studied and applied in long haulage heavyduty (HD) truck engines. The focus of this paper isto characterize an ORC system of a HD long-haulage commercial truck engine that uses single and dual heat sources for WHR. The main objective of this work is to estimate the improvement in the system’s performance when the number of heat sources is increased. Two different WHR configurations: (i) integrated with the engine exhaust and (ii) integrated with both the engine coolant and the exhaust, are studied using the 1D simulation tool GT-Suite. Two types of scroll expanders, adopted from literature, are used in the ORC system configurations to analyze and compare their effect on the overall performance of the engine. Performance of the scroll expanders are generated from their semi-empirical models and R1233zD is used as the working fluid. With engine exhaust as the only heat source, both the expanders exhibit similar performance potentials at their optimum speeds. With two heat sources, fuel-saving is considerably improved, provided the coolant temperature is increased to 120°C and above. For the chosen conditions, expander A, at its optimum coolant temperature of 150oC, leads to around 5.7% fuel-saving; whereas, expander B, at its optimum coolant temperature of 130oC, leads to 5.5% fuel-saving. Further, this paper discusses the effect of expander speeds, expander volumes and superheating on the overall system efficiency.

Keywords
Organic Rankine cycle, waste heat recovery, heavy-duty, volumetric expanders
National Category
Other Mechanical Engineering
Research subject
Machine Design; Machine Design; Machine Design
Identifiers
urn:nbn:se:kth:diva-262825 (URN)
Conference
5th International symposium on ORC power systems, 9 – 11 September 2019, Athens
Projects
Low temperature waste heat recovery
Note

QC 20191024

Available from: 2019-10-21 Created: 2019-10-21 Last updated: 2019-10-24Bibliographically approved
Dahlqvist, J. & Fridh, J. (2017). SEEDGAS INVESTIGATION OF TURBINE STAGE AND SEAL PERFORMANCE AT VARYING CAVITY PURGE RATES AND OPERATING SPEEDS. In: PROCEEDINGS OF THE ASME TURBO EXPO: TURBINE TECHNICAL CONFERENCE AND EXPOSITION, 2017, VOL 2A. Paper presented at PROCEEDINGS OF THE ASME TURBO EXPO 2017. AMER SOC MECHANICAL ENGINEERS
Open this publication in new window or tab >>SEEDGAS INVESTIGATION OF TURBINE STAGE AND SEAL PERFORMANCE AT VARYING CAVITY PURGE RATES AND OPERATING SPEEDS
2017 (English)In: PROCEEDINGS OF THE ASME TURBO EXPO: TURBINE TECHNICAL CONFERENCE AND EXPOSITION, 2017, VOL 2A, AMER SOC MECHANICAL ENGINEERS , 2017Conference paper, Published paper (Refereed)
Abstract [en]

The topic of hub cavity purge is investigated in a high-pressure axial low-reaction turbine stage. Both the sealing ability of the purge flow and the performance impact associated with its injection into the main flow are studied. Three operating speeds are investigated, namely a high loading case, the peak efficiency, and a high speed case, and purge flow rates across a wide range. The operating points coincide with investigations previously reported, where the flow field and stage efficiency was quantified using pneumatic probes. Comparative measurements are also performed, varying a leakage flow through the rotor below the hub platform. The purge flow is now seeded with CO2 in order to measure its distribution throughout the stage, as it is injected into the wheelspace upstream of the rotor, allowing for quantification of the sealing effectiveness. This is done at a number of defined locations along the stator-side wall in the wheel space, resolving the radial variation through the cavity. Important radial variations of effectiveness are observed, confirming that the flow is in the regime of merged boundary layers, due to the narrow cavity, as compared to typical gas turbine operation with separated. boundary layers. The trends are found to be related to operating speed and platform leakage. With known sealing effectiveness, industry correlations may be adapted to make use of the variation of necessary purge rate to obtain a certain degree of sealing at a given operating point, and thereby optimize the efficiency. In addition to quantification of potential hot-gas ingestion, the paper initiates an investigation of the transport of the purge flow in the main annulus, through sampling on the hub, as well as area traverse downstream of the rotor. The amount of sealing gas leads to opportunity to quantify the cooling performance of the purge flow in the main annulus. Both the cooling performance in the main annulus and cavity are shown to be significantly influenced by the rotor leakage, while its effect on efficiency is minor.

Place, publisher, year, edition, pages
AMER SOC MECHANICAL ENGINEERS, 2017
National Category
Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:kth:diva-217086 (URN)10.1115/GT2017-64295 (DOI)000412624400068 ()2-s2.0-85028981739 (Scopus ID)
Conference
PROCEEDINGS OF THE ASME TURBO EXPO 2017
Note

QC 20171106

Available from: 2017-11-06 Created: 2017-11-06 Last updated: 2018-06-19Bibliographically approved
Thiyagarajan, J., Halldorf, E. & Fridh, J. (2017). TRANSIENT THRUST FORCES ON A TWIN SCROLL TURBOCHARGER. In: PROCEEDINGS OF THE ASME TURBO EXPO: TURBINE TECHNICAL CONFERENCE AND EXPOSITION, 2017, VOL 8. Paper presented at Turbo Expo: Turbomachinery Technical Conference & Exposition. AMER SOC MECHANICAL ENGINEERS
Open this publication in new window or tab >>TRANSIENT THRUST FORCES ON A TWIN SCROLL TURBOCHARGER
2017 (English)In: PROCEEDINGS OF THE ASME TURBO EXPO: TURBINE TECHNICAL CONFERENCE AND EXPOSITION, 2017, VOL 8, AMER SOC MECHANICAL ENGINEERS , 2017Conference paper, Published paper (Refereed)
Abstract [en]

The bearing system of turbochargers used in trucks needs to be optimized in order to reduce the frictional losses. This helps in transmitting the exhaust energy more efficiently to the compressor wheel to increase boost pressure. Understanding the thrust loading on the axial bearing helps in optimal design of the bearing and the associated lubrication system. With the advent of twin scroll turbochargers, it is necessary to understand the thrust load behaviour at different operating conditions. This paper pioneers in studying the unsteady axial loads measured on a twin scroll turbocharger mounted on a 6 cylinder 13 litre diesel engine used in the truck industry along with the corresponding analytical predictions for varied engine speeds and loading conditions. Transient thrust forces were measured using a weakened bearing in the experimental approach along with transient pressure measurments on the turbocharger The axial bearing weakening required a design trade-off between flexibility and rigidity of the bearing. The results from the experimental and analytical methods provide better understanding of the characteristics of transient thrust forces that act on a turbocharger mounted on an engine of a heavy duty truck along with its design implications. The maximum normalized axial load measured and predicted were -90 N and -100 N, respectively.

Place, publisher, year, edition, pages
AMER SOC MECHANICAL ENGINEERS, 2017
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Identifiers
urn:nbn:se:kth:diva-217075 (URN)000412862600009 ()
Conference
Turbo Expo: Turbomachinery Technical Conference & Exposition
Note

QC 20171121

Available from: 2017-11-21 Created: 2017-11-21 Last updated: 2018-03-12Bibliographically approved
Saha, R. & Fridh, J. (2015). Aerodynamic Investigation of External Cooling and Applicability of Superposition. In: 11th EUROPEAN CONFERENCE ON TURBOMACHINERY FLUID DYNAMICS AND THERMODYNAMICS: . Paper presented at 11th EUROPEAN CONFERENCE ON TURBOMACHINERY FLUID DYNAMICS AND THERMODYNAMICS, Madrid Spain, MAR 23-26, 2015. EUROPEAN TURBOMACHINERY SOC-EUROTURBO
Open this publication in new window or tab >>Aerodynamic Investigation of External Cooling and Applicability of Superposition
2015 (English)In: 11th EUROPEAN CONFERENCE ON TURBOMACHINERY FLUID DYNAMICS AND THERMODYNAMICS, EUROPEAN TURBOMACHINERY SOC-EUROTURBO , 2015Conference paper, Published paper (Other academic)
Abstract [en]

An experimental investigation of the overall external cooling on a cooled nozzle guide vanehas been conducted in a transonic annular sector cascade. The investigated vane is a typicaltransonic high pressure gas turbine vane, geometrically similar to a real engine component.The investigations are performed for various coolant-to-mainstream mass-flux ratios. Resultsindicate that the aerodynamic loss is influenced substantially with the change of the coolingflow. Area-averaged exit flow angles in midspan region are unaffected at moderate filmcoolant flows, for all cooling configurations except for trailing edge cooling. The trailing edgecooling decreases the turning in all investigated cases. Results lead to a conclusion that bothtrailing edge and suction side cooling have significant influence on the aerodynamic losswhereas the shower head cooling is less sensitive to the loss. Investigations with individualcooling features essentially lead to the applicability of the superposition technique regardingthe aerodynamic loss for film cooled vanes, which is this paper’s contribution to the researchfield. Results show that the superposition technique can be used for the profile loss but not forthe secondary loss.

Place, publisher, year, edition, pages
EUROPEAN TURBOMACHINERY SOC-EUROTURBO, 2015
Keywords
Aerodynamic loss, film cooling, trailing edge cooling, nozzle guide vane, superposition
National Category
Aerospace Engineering Applied Mechanics Energy Engineering
Research subject
Aerospace Engineering; Energy Technology
Identifiers
urn:nbn:se:kth:diva-150455 (URN)000380606100056 ()2-s2.0-85043430645 (Scopus ID)
Conference
11th EUROPEAN CONFERENCE ON TURBOMACHINERY FLUID DYNAMICS AND THERMODYNAMICS, Madrid Spain, MAR 23-26, 2015
Note

QC 20161111

Available from: 2014-09-04 Created: 2014-09-04 Last updated: 2018-05-16Bibliographically approved
Mamaev, B., Saha, R. & Fridh, J. (2015). Aerodynamic investigation of turbine cooled vane block. Thermal Engineering, 62(2), 97-102
Open this publication in new window or tab >>Aerodynamic investigation of turbine cooled vane block
2015 (English)In: Thermal Engineering, ISSN 0040-6015, Vol. 62, no 2, p. 97-102Article in journal (Refereed) Published
Abstract [en]

The vane block (VB) has been investigated and it gives several important results related to test methods and calculation procedures. The vane block is characterized by a developed film and convective cooling system. Blowing tests demonstrate that there is a weak correlation between cooling type and energy loss. Superposition of these effects is true for the central part over VB height without secondary flows. Coolant discharge increases profile loss and it rises if coolant flow rate is increased. Discharge onto profile convex side through the trailing edge slot influences the most considerably. The discharge through perforation decreases the vane flow capacity and insufficiently influences onto the flow outlet angle, but the trailing edge discharge increases this angle according to loss and mixture flow rate growth. The secondary flows reduce the effect of coolant discharge, which insufficiently changes losses distribution at turbine blades tips and even decreases the secondary losses. The flow outlet angle rises significantly and we are able to calculate it only if we correct the ordinary flow model. In the area of secondary flows, the outlet angle varies insufficiently under any type of cooling. This area should be investigated additionally.

National Category
Aerospace Engineering Energy Engineering
Research subject
Aerospace Engineering; Energy Technology
Identifiers
urn:nbn:se:kth:diva-159585 (URN)10.1134/S0040601515020068 (DOI)2-s2.0-84927600902 (Scopus ID)
Note

QC 20150331

Available from: 2015-02-04 Created: 2015-02-04 Last updated: 2015-03-31Bibliographically approved
Dahlqvist, J. & Fridh, J. (2015). Experimental flow and performance investigations of cavity purge flows in a high pressure turbine stage. In: 11th European Conference on Turbomachinery Fluid Dynamics and Thermodynamics, ETC 2015: . Paper presented at 11th European Conference on Turbomachinery Fluid Dynamics and Thermodynamics, ETC 2015, 23 March 2015 through 27 March 2015. European Conference on Turbomachinery (ETC)
Open this publication in new window or tab >>Experimental flow and performance investigations of cavity purge flows in a high pressure turbine stage
2015 (English)In: 11th European Conference on Turbomachinery Fluid Dynamics and Thermodynamics, ETC 2015, European Conference on Turbomachinery (ETC) , 2015Conference paper, Published paper (Refereed)
Abstract [en]

A high pressure turbine stage has been investigated from the aspect of flow and performance impact associated with cavity purge. Performance is referred to as the operating parameters of the turbine, mainly based on the continuous output torque monitoring. The flow parameters were studied through measurements featuring temperature and pressure throughout the flow path, as well as in the cavity. Purge and main flow velocities were quantified in the vane exit section, and degree of sealing based on purge-amount correlations and pressure readings. Results were related to turbine efficiency based on a simple correlation, and also entropy generation. Change of operating point was found to have a significant effect on degree of sealing, while the change of efficiency was found to be linear with respect to relative purge rate and independent of operating point.

Place, publisher, year, edition, pages
European Conference on Turbomachinery (ETC), 2015
Keywords
Entropy, Fluid dynamics, Gas turbines, Thermodynamics, Turbomachinery, Entropy generation, High pressure turbine stage, Operating parameters, Operating points, Performance impact, Pressure reading, Temperature and pressures, Turbine efficiency, Turbines
National Category
Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:kth:diva-174784 (URN)000380606100084 ()2-s2.0-85043422715 (Scopus ID)9780000000002 (ISBN)
Conference
11th European Conference on Turbomachinery Fluid Dynamics and Thermodynamics, ETC 2015, 23 March 2015 through 27 March 2015
Funder
Swedish Energy Agency
Note

QC 20151208

Available from: 2015-12-08 Created: 2015-10-07 Last updated: 2018-05-16Bibliographically approved
El-Gabry, L., Saha, R., Fridh, J. & Fransson, T. (2015). Measurements of Hub Flow Interaction on Film Cooled Nozzle Guide Vane in Transonic Annular Cascade. Journal of turbomachinery, 137(8), Article ID 081004.
Open this publication in new window or tab >>Measurements of Hub Flow Interaction on Film Cooled Nozzle Guide Vane in Transonic Annular Cascade
2015 (English)In: Journal of turbomachinery, ISSN 0889-504X, E-ISSN 1528-8900, Vol. 137, no 8, article id 081004Article in journal (Refereed) Published
Abstract [en]

An experimental study has been performed in a transonic annular sector cascade of nozzle guide vanes (NGVs) to investigate the aerodynamic performance and the interaction between hub film cooling and mainstream flow. The focus of the study is on the endwalls, specifically the interaction between the hub film cooling and the mainstream. Carbon dioxide (CO2) has been supplied to the coolant holes to serve as tracer gas. Measurements of CO2 concentration downstream of the vane trailing edge (TE) can be used to visualize the mixing of the coolant flow with the mainstream. Flow field measurements are performed in the downstream plane with a five-hole probe to characterize the aerodynamics in the vane. Results are presented for the fully cooled and partially cooled vane (only hub cooling) configurations. Data presented at the downstream plane include concentration contour, axial vorticity, velocity vectors, and yaw and pitch angles. From these investigations, secondary flow structures such as the horseshoe vortex, passage vortex, can be identified and show the cooling flow significantly impacts the secondary flow and downstream flow field. The results suggest that there is a region on the pressure side (PS) of the vane TE where the coolant concentrations are very low suggesting that the cooling air introduced at the platform upstream of the leading edge (LE) does not reach the PS endwall, potentially creating a local hotspot.

National Category
Aerospace Engineering Applied Mechanics Energy Engineering
Research subject
Aerospace Engineering; Energy Technology
Identifiers
urn:nbn:se:kth:diva-159584 (URN)10.1115/1.4029242 (DOI)000356835400004 ()2-s2.0-84937040916 (Scopus ID)
Note

QC 20150224

Available from: 2015-02-04 Created: 2015-02-04 Last updated: 2019-09-20Bibliographically approved
Alameldin, A., El-Gabry, L. A., Fridh, J. & Saha, R. (2014). CFD analysis of suction and pressure side film cooling influence on vane aero performance in a transonic annular cascade. In: Proceedings of the ASME Turbo Expo: . Paper presented at ASME Turbo Expo 2014: Turbine Technical Conference and Exposition, GT 2014, 16 June 2014 through 20 June 2014.
Open this publication in new window or tab >>CFD analysis of suction and pressure side film cooling influence on vane aero performance in a transonic annular cascade
2014 (English)In: Proceedings of the ASME Turbo Expo, 2014Conference paper, Published paper (Refereed)
Abstract [en]

Operating at temperatures well above their melting point, gas turbines' components are subject to terribly high thermal stresses. In order to keep them intact and performing, different cooling techniques are implemented. One of these methods is film cooling. Film cooling implementation in vane cascades has a potential loss expense. Proper assessment of its impact on the vane performance has to be conducted. The CFD approach of modeling each hole and cooling tube autonomously is very computationally expensive. In the current work an assessment of a new, more computationally efficient CFD approach for modelling film cooling was conducted on a vane cascade operating in the transonic regime (M =0.89). The film cooling holes were represented by orifice boundary condition at the vane surface, omitting the need to model internal coolant plenum and cooling tubes mesh, resulting in 180% reduction in grid size and attributed computational cost interpreted in 300% saving in computation time. Uncooled, and film cooled with different configurations and at different blowing ratios (BR) simulations were performed and compared to experimental measurements. A good agreement was obtained for the exit flow angles, vorticity and aerodynamic loss for all the cases (uncooled and cooled). Pitch-averaged exit flow angle outside endwalls regions remains unchanged for all cooling configurations and blowing ratios. The aerodynamic loss was found to be more sensitive to increasing the blowing ratio on the suction side than on the pressure side. The proposed approach of coolant injection modeling is shown to yield reliable results, within the uncertainty of the measurements in most cases. Along with lower computational cost compared to conventional film cooling modeling approach, the new approach is recommended for further analysis for aero and thermal vane cascade flows.

Keywords
Aerodynamics, Computational fluid dynamics, Coolants, Cost benefit analysis, Gas turbines, Transonic aerodynamics, Tubes (components), Uncertainty analysis, Computational costs, Computationally efficient, Coolant injection, Cooling configuration, Cooling technique, Film cooling hole, Reliable results, Transonic annular cascade, Cooling
National Category
Energy Engineering
Identifiers
urn:nbn:se:kth:diva-167519 (URN)10.1115/GT2014-26617 (DOI)000361923200040 ()2-s2.0-84922254911 (Scopus ID)9780791845622 (ISBN)
Conference
ASME Turbo Expo 2014: Turbine Technical Conference and Exposition, GT 2014, 16 June 2014 through 20 June 2014
Note

QC 20150611

Available from: 2015-06-11 Created: 2015-05-22 Last updated: 2015-10-29Bibliographically approved
Saha, R., Mamaev, B., Fridh, J., Laumert, B. & Fransson, T. (2014). Influence of Prehistory and Leading Edge Contouring on Aero Performance of a Three-Dimensional Nozzle Guide Vane. Journal of turbomachinery, 136(7), 071014-1-071014-10
Open this publication in new window or tab >>Influence of Prehistory and Leading Edge Contouring on Aero Performance of a Three-Dimensional Nozzle Guide Vane
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2014 (English)In: Journal of turbomachinery, ISSN 0889-504X, E-ISSN 1528-8900, Vol. 136, no 7, p. 071014-1-071014-10Article in journal (Refereed) Published
Abstract [en]

Experiments are conducted to investigate the effect of the prehistory in the aerodynamic performance of a three-dimensional nozzle guide vane with a hub leading edge contouring. The performance is determined with two pneumatic probes (five hole and three hole) concentrating mainly on the end wall. The investigated vane is a geometrically similar gas turbine vane for the first stage with a reference exit Mach number of 0.9. Results are compared for the baseline and filleted cases for a wide range of operating exit Mach numbers from 0.5 to 0.9. The presented data includes loading distributions, loss distributions, fields of exit flow angles, velocity vector, and vorticity contour, as well as mass-averaged loss coefficients. The results show an insignificant influence of the leading edge fillet on the performance of the vane. However, the prehistory (inlet condition) affects significantly in the secondary loss. Additionally, an oil visualization technique yields information about the streamlines on the solid vane surface, which allows identifying the locations of secondary flow vortices, stagnation line, and saddle point.

Place, publisher, year, edition, pages
ASME Press, 2014
Keywords
Secondary Flows, Blade Passage, Fillets
National Category
Aerospace Engineering Applied Mechanics Energy Engineering
Research subject
SRA - Energy
Identifiers
urn:nbn:se:kth:diva-139946 (URN)10.1115/1.4026076 (DOI)000335964100014 ()2-s2.0-84994246462 (Scopus ID)
Funder
Swedish Energy Agency
Note

QC 20140612

Available from: 2014-01-15 Created: 2014-01-15 Last updated: 2017-12-06Bibliographically approved
Saha, R., Fridh, J., Fransson, T., Mamaev, B., Annerfeldt, M. & Utriainen, E. (2014). Shower Head and Trailing Edge Cooling Influence on Transonic Vane Aero Performance. In: ASME Turbo Expo 2014: Turbine Technical Conference and Exposition. Paper presented at ASME Turbo Expo 2014: Turbine Technical Conference and Exposition, GT 2014, Dusseldorf, Germany, 16 June 2014 through 20 June 2014. ASME Press
Open this publication in new window or tab >>Shower Head and Trailing Edge Cooling Influence on Transonic Vane Aero Performance
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2014 (English)In: ASME Turbo Expo 2014: Turbine Technical Conference and Exposition, ASME Press, 2014Conference paper, Published paper (Refereed)
Abstract [en]

An experimental investigation on a cooled nozzle guide vane has been conducted in an annular sector to quantify aerodynamic influences of shower head and trailing edge cooling. The investigated vane is a typical high pressure gas turbine vane, geometrically similar to a real engine component, operated at a reference exit Mach number of 0.89. The investigations have been performed for various coolant-to-mainstream mass-flux ratios. New loss equations are derived and implemented regarding coolant aerodynamic losses. Results lead to a conclusion that both trailing edge cooling and shower head film cooling increase the aerodynamic loss compared to an uncooled case. In addition, the trailing edge cooling has higher aerodynamic loss compared to the shower head cooling. Secondary losses decrease with inserting shower head film cooling compared to the uncooled case. The trailing edge cooling appears to have less impact on the secondary loss compared to the shower head cooling. Area-averaged exit flow angles around midspan increase for the trailing edge cooling.

Place, publisher, year, edition, pages
ASME Press, 2014
Keywords
Aerodynamic loss, Film cooling, Nozzle guide vane, Shower head cooling, Trailing edge cooling
National Category
Aerospace Engineering Applied Mechanics Energy Engineering
Research subject
Aerospace Engineering; Energy Technology
Identifiers
urn:nbn:se:kth:diva-148423 (URN)10.1115/GT2014-25613 (DOI)000361923200018 ()2-s2.0-84922224108 (Scopus ID)978-079184562-2 (ISBN)
Conference
ASME Turbo Expo 2014: Turbine Technical Conference and Exposition, GT 2014, Dusseldorf, Germany, 16 June 2014 through 20 June 2014
Projects
Sector rig
Note

QC 20150217

Available from: 2014-08-07 Created: 2014-08-07 Last updated: 2015-10-29Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-1033-9601

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