Performance of a Mixed Flow Turbocharger Turbine Under Pulsating Flow Conditions

Arcoumanis, C.; Hakeem, I; Khezzar, Lyes; Martinez-Botas, Ricardo; Baines, N. C.

doi:10.1115/95-gt-210

Cited by 39 publications

(18 citation statements)

References 3 publications

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“…Winterbone et al [3] and Nikpour [4] also designed a facility and used a hydraulic dynamometer in order to perform torque measurements. Arcoumanis et al [5] used a radial compressor instead of a dynamometer to enable increased power of larger turbines to be absorbed. Szymko [6] developed an installation where an eddy current dynamometer was used in order to absorb the power of the turbine and for providing a low known inertia of the rotating assembly, which increases the measurement accuracy of the instantaneous torque.…”

Section: Introductionmentioning

confidence: 99%

A physically based methodology to extrapolate performance maps of radial turbines

Payri

Serrano

Fajardo

et al. 2012

Energy Conversion and Management

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This paper details a physical based methodology to perform an extrapolation of the radial turbine performance maps, both mass flow characteristics and the efficiency curve. This method takes into account a narrow range of experimental data, which is usually the data available when such turbines are part of a turbocharger. Therefore, the extrapolation methodology is especially useful when data from third parties are being used or when the compressor of a turbocharger is used as turbine brake in a gas stand. The nozzle equation is used to develop an interpolation and extrapolation of the mass flow rate trough the turbine. Then, specific information is extracted from this extrapolation and is fed into a total-to-static efficiency equation to carry out an extension of the efficiency curve. This equation is developed using the definition of the total-to-static efficiency, velocity triangles and thermodynamic and fluid fundamental equations.This procedure has been applied to five radial turbines of different sizes and types. Results are compared against experimental information available in the literature or provided by the turbine manufacturers and a good agreement has been found between theoretical and experimentally estimated data.Keywords: Turbochargers, radial turbines, efficiency and mass flow rate maps extrapolation, physical equations based extrapolation. ------------------------------- Greek --------------------------------- Subscripts INTRODUCTIONA way to characterize the performance of a radial inflow turbine widely used in a turbocharger is via a turbine map. Turbine maps usually are presented using two separate plots: one for the mass flow rate and one for the energy conversion efficiency, which usually is taken as the total-to-static efficiency. The former chart is presented as the corrected mass flow ( * m  ) as a function of the totalto-static expansion ratio (ER). The corrected mass flow ( * m  ) is defined as the mass flow rate multiplied by a ratio between the square root of the turbine stagnation inlet temperature and the turbine stagnation inlet pressure [1]. The other chart is the total-to-static efficiency ( ts ) as a function of the blade to jet speed ratio (), which is a ratio of the rotor tip linear velocity to the isentropic velocity through the turbine stage, for different turbine rotational speeds [1]. [5] used a radial compressor instead of a dynamometer to enable increased power of larger turbines to be absorbed. Szymko [6] developed an installation where an eddy current dynamometer was used in order to absorb the power of the turbine and for providing a low known inertia of the rotating assembly, which increases the measurement accuracy of the instantaneous torque.In the continuous flow test bench at Universidad Politécnica de Valencia, the approach is to use a compressor as a braking device [7]. In this last case, a collection of only a narrow range of data is possible, due to the surge and choke limits of the compressor, so a limited widespread of the data is availabl...

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Section: Introductionmentioning

confidence: 99%

A physically based methodology to extrapolate performance maps of radial turbines

Payri

Serrano

Fajardo

et al. 2012

Energy Conversion and Management

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“…The experimental facility used in this study is a simulated reciprocating engine test bed for turbocharger testing. The facility has the capability of conducting steady and unsteady testing with simulated engine pulsations, as previously reported [3,4]. Furthermore, the latest instalment of eddy current dynamometer enables turbine testing within a larger velocity ratio range [11,12].…”

Section: Methodsmentioning

confidence: 99%

“…Research has shown a substantial amount of exhaust gas energy to be available at velocity ratios of less than 0.7 -the point of highest energy recovery for a conventional radial turbine. For the past three decades research has been carried out to explore the benefits of the mixed flow turbine in terms of lower velocity ratio operation and higher swallowing capacity [1,2,3,4]. For a non-zero rotor blade angle, the peak turbine efficiency point moves to a higher expansion ratio.…”

Section: Introductionmentioning

confidence: 99%

“…Most available published work on VGT is still based on steady-state data. It has been shown in the past research that a turbine's performance during pulsating flow departs from the quasi-steady assumption [3,4,6,7], however most of these work were based on nozzleless turbines. Thus the instantaneous performance evaluation of a VGT in pulsating flow conditions is beneficial in order to better understand its characteristics at different nozzle vane positions.…”

Section: Introductionmentioning

confidence: 99%

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Variable Geometry Mixed Flow Turbine for Turbochargers: An Experimental Study

Rajoo

Martinez-Botas

2008

International Journal of Fluid Machinery and Systems

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This paper investigates a variable geometry (VG) mixed flow turbine with a novel, purposely designed pivoting nozzle vane ring. The nozzle vane ring was matched to the 3-dimensional aspect of the mixed flow rotor leading edge with lean stacking. It was found that for a nozzle vane ring in a volute, the vane surface pressure is highly affected by the flow in the volute rather than the adjacent vane surface interactions, especially at closer nozzle positions. The performance of the VG mixed flow turbine has been evaluated experimentally in steady and unsteady flow conditions. The VG mixed flow turbine shows higher peak efficiency and swallowing capacity at various vane angle settings compared to an equivalent nozzleless turbine. Comparison with an equivalent straight vane arrangement shows a higher swallowing capacity but similar efficiencies. The VG turbine unsteady performance was found to deviate substantially from the quasi-steady assumption compared to a nozzleless turbine. This is more evident in the higher vane angle settings (smaller nozzle passage), where there are high possibility of choking during a pulse cycle. The presented steady and unsteady results are expected to be beneficial in the design of variable geometry turbochargers, especially the ones with a mixed flow turbine.

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“…The second is the distance separating the two measurements planes which cannot be clearly defined without a detailed evaluation of the path-lines, since the twinentry volute feeds the rotor circumferentially around 360 deg. Palfreyman and Martinez-Botas [13] and Arcoumanis et al [26] showed that the time shift is mainly produced in the volute owing to its biggest characteristic length as compared to the rotor which may be studied as a quasi-steady pattern. Therefore, in the present study the time shift is taken as the necessary time for the mechanism of pulse to travel from the inlet duct to the exit volute; hence the time shift is expressed as = ,…”

Section: Instantaneous Isentropic and Actualmentioning

confidence: 99%

Characterization of a Twin-Entry Radial Turbine under Pulsatile Flow Condition

Cerdoun

Ghenaiet

2016

International Journal of Rotating Machinery

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In automotive applications radial gas turbines are commonly fitted with a twin-entry volute connected to a divided exhaust manifold, ensuring a better scavenge process owing to less interference between engines’ cylinders. This paper is concerned with the study of the unsteady performances related to the pulsating flows of a twin-entry radial turbine in engine-like conditions and the hysteresis-like behaviour during the pulses period. The results show that the aerodynamic performances deviate noticeably from the steady state and depend mainly on the time shifting between the actual output power and the isentropic power, which is distantly related to the apparent length. The maximum of efficiency and output shaft power are accompanied by low entropy generation through the shroud entry side, and their instantaneous behaviours tend to follow mainly the inlet total pressure curve. As revealed a billow is created by the interaction between the main flow and the infiltrated flow, affecting the flow incidence at rotor entry and producing high losses.

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Performance of a Mixed Flow Turbocharger Turbine Under Pulsating Flow Conditions

Cited by 39 publications

References 3 publications

A physically based methodology to extrapolate performance maps of radial turbines

A physically based methodology to extrapolate performance maps of radial turbines

Variable Geometry Mixed Flow Turbine for Turbochargers: An Experimental Study

Characterization of a Twin-Entry Radial Turbine under Pulsatile Flow Condition

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