Variable Geometry Mixed Flow Turbine for Turbochargers: An Experimental Study

Rajoo, Srithar; Martinez-Botas, Ricardo

doi:10.5293/ijfms.2008.1.1.155

Cited by 32 publications

(21 citation statements)

References 10 publications

(22 reference statements)

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“…The pulsating air flow simulating engine exhaust flow is produced by a pulse generator, made of two chopper plates with specified cut-out shape. Turbine output power is absorbed by an in-house developed eddy current dynamometer [20] which enables wider performance map measurement, compared to conventional compressor loadings [15][16][17].…”

Section: Experimental Methodsmentioning

confidence: 99%

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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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Section: Experimental Methodsmentioning

confidence: 99%

“…It has been shown that turbine behavior under the highly unsteady flow deviates from its equivalent steady performance [15][16][17][18]. There are limited documented investigations on the effects of volute cross-sectional shape on a turbine performance under pulsating flow conditions.…”

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

Self Cite

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“…15,40,41 Some researchers indicated that pulse frequency was not as important as pulse amplitude in the performance of the system. 17,23,42 A recent simulation showed that for fixed amplitude of mass flow variation over a pulse, increasing pulse frequency increased the range of incidence, increasing the unsteadiness, thus lowering the efficiency. 21 Given the qualitative trends of increasing orbit variation with increases in frequency for fixed amplitude of oscillations 17,28 , frequency is seen to enhance unsteadiness, which leads to higher off-design losses and contradicts the claim for increased efficiency.…”

Section: Parametric Variations In Pulsed Flow Turbinesmentioning

confidence: 99%

Trends in Pulsating Turbine Performance: Pulse-Detonation Driven Axial Flow Turbine

George

Gutmark

2012

50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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An investigation of previous studies involving turbines driven by pulsating, unsteady flows is conducted. The suitability of conventional steady flow performance metrics for application to the case of pulsating flow is discussed, with a focus on the observed deviation from quasi-steady behavior. This deviation is found to be a strong function of upstream geometry, pulse form and amplitude, and disparity between the time scales of the pulse and of the rotor dynamics. Existing studies exhibit controversy as to the effects of parametric variation of pulsating flow quantities on the turbine performance as well as suitable metrics to describe this performance. These studies are used to predict qualitative trends for the performance of an integrated pulse-detonation driven axial turbine. Trends from current experimental studies of pulse-detonation driven flows are examined to assess these hypotheses. Nomenclaturea = Sonic Velocity (m/s) PDC = Pulse Detonation Combustion AF = Amplitude Factor PDE = Pulse Detonation Engine BSR = Blade Speed Ratio, Velocity Ratio PMSt = Pressure Modified Strouhal Number C = Absolute Flow Velocity (m/s) PR = Pressure Ratio c p = Specific Heat at Constant Pressure (J/kg·K) QSF = Quasi-Steady Flow CVC = Constant Volume Combustion St = Strouhal Number d = Diameter (m) T = Temperature (K) f = Frequency of Pulsation (Hz) U = Rotor Tip (Blade) Speed (m/s) h = Specific Enthalpy (J/kg) v = Mean Flow Velocity (m/s) L = Characteristic Length (m) W = Relative Flow Velocity (m/s) ṁ = Mass Flow Rate (kg/s) x = Arbitrary Spatial Location MFP = Mass Flow Parameter (K ½ ·s/m) β = Reduced Frequency MSt = Modified Strouhal Number γ = Ratio of Specific Heats N = Turbine Speed (rad/s) η = Efficiency T N / = Normalized Turbine Speed (rad/K ½ s) φ = Duty Cycle P = Power (W), Pressure (Pa) τ = Torque (N·m) ω = Frequency of Pulsation (rad/s)

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“…A 3-dimensional nozzle vane ring was introduced by [11] in an attempt to supply optimum inflow characteristics to the mixed flow rotor. The steady state results showed an improvement in efficiency over a nozzleless design at higher vane angle settings.…”

Section: The Introduction Of a Tilted Volute Design For Operation Witmentioning

confidence: 99%

The introduction of a tilted volute design for operation with a mixed flow turbine for turbocharger applications

Lee

Jupp

Nickson

2016

2016 7th International Conference on Mechanical and Aerospace Engineering (ICMAE)

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Variable Geometry Mixed Flow Turbine for Turbochargers: An Experimental Study

Cited by 32 publications

References 10 publications

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

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

Trends in Pulsating Turbine Performance: Pulse-Detonation Driven Axial Flow Turbine

The introduction of a tilted volute design for operation with a mixed flow turbine for turbocharger applications

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