Effect of volute geometry on the steady and unsteady performance of mixed-flow turbines

Hakeem, I; Su, C. C.; Costall, Aaron; Martinez-Botas, Ricardo

doi:10.1243/09576509jpe314

Cited by 26 publications

(23 citation statements)

References 18 publications

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“…The efficiency shows hysteresis-like behaviour that has also reported in other studies for mixed flow turbines [5,16]. The area covered by the pulse period is larger at plane E than at the trailing edge.…”

Section: Time-accurate Performance With Pulsatile Inlet Flowsupporting

confidence: 84%

“…Hysteresis-like behaviour is seen during the pulse period. Similar kind of behaviour has also been found in papers studying mixed flow turbines [5,16]. The behaviour in the studied case is relatively symmetrical compared to the studies in the literature.…”

Section: Time-accurate Performance With Pulsatile Inlet Flowsupporting

confidence: 84%

“…The efficiencies have been calculated starting from the trailing edge in positions C, D, E and F. The efficiency decreases when the distance from the trailing edge increases, which is common for all of the modelling approaches. The efficiencies of quasi-steady modelling are slightly lower than those of time-accurate and pulsatile-inlet modelling, except in plane D. In the papers of Lam [4] and Hakeem et al [16], the performance of the turbocharger turbine was overestimated when averaging methods almost similar to Equation 4 were used. Two averaging methods out of three predicted the pulsatile performance of the turbine to be worse than the steady state performance [4].…”

Section: Grid Dependency Studymentioning

confidence: 99%

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Numerical modelling of a supersonic axial turbine stator

et al. 2010

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In order to improve the turbocharging process, a supersonic axial turbine stator was modelled numerically with a pulsatile inlet mass flow. The main objectives of the study were to find out how pulsation affects the flow field and the performance of the stator. At the beginning of the study, a supersonic turbine stator was modelled using three different techniques: quasi-steady, time-accurate with constant boundary conditions and time-accurate with a pulsatile inlet mass flow. The time-averaged and quasi-steady flow fields and performance were compared, and the flow field and stator performance with a pulsatile inlet mass flow was studied in detail at different time-steps.A hysteresis-like behaviour was captured when the total-to-static pressure ratio and efficiency were plotted as a function of the inlet mass flow over one pulse period. The total-to-static pressure ratio and efficiency followed the sinusoidal shape of the inlet flow as a function of time. It was also concluded that the stator efficiency decreases downstream from the stator trailing edge and the amplitude of the pulsating mass flow is decreased at the stator throat.

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Section: Time-accurate Performance With Pulsatile Inlet Flowsupporting

confidence: 84%

Section: Time-accurate Performance With Pulsatile Inlet Flowsupporting

confidence: 84%

Section: Grid Dependency Studymentioning

confidence: 99%

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Numerical modelling of a supersonic axial turbine stator

et al. 2010

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“…There are limited documented investigations on the effects of volute cross-sectional shape on a turbine performance under pulsating flow conditions. One such research was by Hakeem et al [19], where a volute with approximately trapezoidal cross-sectional shape was modified into an approximately elliptic shape. This was achieved by rounding the corners and consequently tested with a mixed-flow turbine rotor.…”

Section: Introductionmentioning

confidence: 99%

An investigation of volute cross-sectional shape on turbocharger turbine under pulsating conditions in internal combustion engine

Yang

Martinez-Botas

Rajoo

et al. 2015

Energy Conversion and Management

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a b s t r a c tEngine downsizing is a proven method for CO 2 reduction in Internal Combustion Engine (ICE). A turbocharger, which reclaims the energy from the exhaust gas to boost the intake air, can effectively improve the power density of the engine thus is one of the key enablers to achieve the engine downsizing. Acknowledging its importance, many research efforts have gone into improving a turbocharger performance, which includes turbine volute. The cross-section design of a turbine volute in a turbocharger is usually a compromise between the engine level packaging and desired performance. Thus, it is beneficial to evaluate the effects of cross-sectional shape on a turbine performance. This paper presents experimental and computational investigation of the influence of volute cross-sectional shape on the performance of a radial turbocharger turbine under pulsating conditions. The cross-sectional shape of the baseline volute (denoted as Volute B) was optimized (Volute A) while the annulus distribution of area-to-radius ratio (A/R) for the two volute configurations are kept the same. Experimental results show that the turbine with the optimized volute A has better cycle averaged efficiency under pulsating flow conditions, for different loadings and frequencies. The advantage of performance is influenced by the operational conditions. After the experiment, a validated unsteady computational fluid dynamics (CFD) modeling was employed to investigate the mechanism by which performance differs between the baseline volute and the optimized version. Computational results show a stronger flow distortion in spanwise direction at the rotor inlet with the baseline volute. Furthermore, compared with the optimized volute, the flow distortion is more sensitive to the pulsating flow conditions in the baseline volute. This is due to the different secondary flow pattern in the cross-sections, hence demonstrating a direction for desired volute cross-sectional shape to be used in a turbocharger radial turbine for internal combustion engine.

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“…The general opinion is that the impeller can be treated as quasi-stationary, whereas almost all the accumulation and wave effects are located in the volute [9,10]. Hakeem et al [11] tested the influence of the volute geometry in turbine performance under steady and unsteady conditions, showing differences in the observed behaviour between steady-state and unsteady tests. Although done for a radial compressor, Abdelmadjid et al [12] showed big effects in compressor performance due to variations in its volute geometry using CFD simulations.…”

Section: Introductionmentioning

confidence: 99%

Development and validation of a radial variable geometry turbine model for transient pulsating flow applications

Galindo

Tiseira

Fajardo

et al. 2014

Energy Conversion and Management

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Elsevier Galindo, J.; Tiseira Izaguirre, AO.; Fajardo, P.; García-Cuevas González, LM. (2014). Development and validation of a radial variable geometry turbine model for transient pulsating flow applications. Energy AbstractThis paper presents the development and validation of a one-dimensional radial turbine model able to be used in automotive turbocharger simulations. The model has been validated using results from a numerical 3D CFD simulation of stationary and pulsating flow in a variable geometry radial turbine. As the CFD analysis showed, the main non-quasi-steady behavior of the turbine is due to the volute geometry, so special care was taken in order to properly model it while maintaining low computational costs. The flow in the volute has been decomposed in its radial and azimuthal direction. The azimuthal flow corresponds to the flow moving along the volute, while the radial flow is computed by coupling its flow with a stator model. Although the stator caused fewer accumulation effects than the volute, a small accumulation model has been used for it, which also allows to compute the evolution of the flow inside the turbine with lower costs. The flow in the moving rotor can be considered quasi-steady, so a zero-dimensional model for the rotor has been developed. Several losses models where implemented for both the stator and the rotor. The results show good agreement with the CFD computations.

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Effect of volute geometry on the steady and unsteady performance of mixed-flow turbines

Cited by 26 publications

References 18 publications

Numerical modelling of a supersonic axial turbine stator

Numerical modelling of a supersonic axial turbine stator

An investigation of volute cross-sectional shape on turbocharger turbine under pulsating conditions in internal combustion engine

Development and validation of a radial variable geometry turbine model for transient pulsating flow applications

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