Investigation of Nozzle Clearance Effects on a Radial Turbine: Aerodynamic Performance and Forced Response

Hu, Liangjun; Sun, Harold; Yi, Jianwen; Curtis, Eric W.; Morelli, Anthony; Zhang, Jizhong; Zhao, Ben; Yang, Ce; Shi, Xiuyong; Liu, Shangtao

doi:10.4271/2013-01-0918

Cited by 20 publications

(10 citation statements)

References 10 publications

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“…Hu et al [4] performed a CFD/FEA coupled analysis in a variable geometry turbine to analyze the static and vibration stress of the rotor blade. The results revealed that nozzle leakage flow increases flow unsteadiness inside the turbine wheel and excitation on the rotor.…”

Section: Introductionmentioning

confidence: 99%

Understanding of the Interaction between Clearance Leakage Flow and Main Passage Flow in a VGT Turbine

Zhao

Yang

et al. 2014

Advances in Mechanical Engineering

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The clearance flow between the nozzle and endwall in a variable geometry turbine (VGT) has been numerically investigated to understand the clearance effect on the VGT performance and internal flow. It was found that the flow rate through turbine increases but the turbine efficiency decreases with height of clearance. Detailed flow field analyses indicated that most of the efficiency loss resulting from the leakage flow occurs at the upstream of the rotor area, that is, in the nozzle endwall clearance and between the nozzle vanes. There are two main mechanisms associated with this efficiency loss. One is due to the formation of the local vortex flow structure between the clearance flow and the main flow. The other is due to the impact of the clearance flow on the main flow after the nozzle throat. This impact reduces the span of shockwave with increased shockwave magnitude by changing the trajectory of the main flow.

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Section: Introductionmentioning

confidence: 99%

Understanding of the Interaction between Clearance Leakage Flow and Main Passage Flow in a VGT Turbine

Zhao

Yang

et al. 2014

Advances in Mechanical Engineering

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“…The reduction means that the nozzle endwall clearance leakage flow is decreased. According to the literature, 19,20 the leakage flow is one of the excitation sources to the vibration of the downstream turbine wheel. Consequently, decreasing the leakage flow through the nozzle vane endwall clearance might benefit the reliability of the downstream turbine wheel.…”

Section: Steady Cfd Simulation and Resultsmentioning

confidence: 99%

Effects of grooved vanes on shock wave and forced response in a turbocharger turbine

Zhao

Shi

Sun

et al. 2019

International Journal of Engine Research

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In radial inflow turbine design, the optimization of turbine geometry for aerodynamic performance improvement is often constrained by the requirement of reliability, thus facing a trade-off. One of the vital challenges for a better trade-off is how to mitigate the forced response of turbine wheel, while maintaining high efficiency, so as to avoid high cycle fatigue failure. In this article, using a grooved surface on nozzle vanes for the forced response reduction was investigated. In light of the fact that the investigation on the high cycle fatigue issue involves both aerodynamic interactions and structural analyses, a customized computer code was developed using MATLAB software to couple computational fluid dynamics simulations with finite element analysis calculations. Partial results were compared against experimental results, respectively, to validate the numerical method. The coupled numerical method reveals that using the grooved surface on the nozzle vane alters the shock wave structure, decreases the peak stress of turbine wheel by 8%, and deteriorates turbine efficiency by 0.05 percentage points.

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“…The main reason for choosing the Spalart-Allmaras turbulence model to calculate the turbulent viscosities is that it can predict the turbine performance well, compared with the test result at nozzle different opening conditions. 15,16,19 As for the boundary conditions, total pressure and total temperature were specified at the nozzle inlet; static pressure was applied at turbine outlet. All of the boundary conditions adopted in the numerical simulations are consistent with the experiments cited in this work.…”

Section: Methodsmentioning

confidence: 99%

“…There are publications that indicate that nozzle leakage flow can induce vibration of rotor blades, which has become one of key factors of high-cycle fatigue failure for turbine. [15][16][17][18][19] In this work, the unsteady simulation results of sections ''Nozzle leakage flow analysis at small nozzle opening'' and ''Shock wave comparison at 40% nozzle opening'' were also further analyzed to study the effect of nozzle leakage flow on rotor blades for both FRGV and baseline models. The root of mean square (RMS) static pressure (f rms ) is introduced here to quantify the unsteady aerodynamic excitation on rotor blades of baseline and FRGV models caused by nozzle leakage flow, which is defined as follows…”

Section: Shock Wave Comparison At 40% Nozzle Openingmentioning

confidence: 99%

A detailed investigation of a variable nozzle turbine with novel forepart rotation guide vane

Yang

Lao

et al. 2018

Proceedings of the Institution of Mechanical Engineers, Part D:

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One of the disadvantages of a variable nozzle turbine in practical application is the stage performance degradation due to nozzle endwall leakage flow at small nozzle openings. Aiming at restricting the nozzle leakage flow rate to improve turbine stage performance, a novel forepart rotation guide vane has been proposed and numerically studied in present work. First, the numerical results of baseline turbine were validated by experimental data to ensure the accuracy of numerical methods. Then steady and unsteady simulations were performed on both baseline and forepart rotation guide vane turbines to demonstrate the effectiveness of the novel vane and to study the characteristics of nozzle leakage flow, respectively. Results indicate that there is up to 13.5% peak efficiency improvement that has been achieved at 10% nozzle opening with the forepart rotation guide vane design; besides, rotor–stator interaction for forepart rotation guide vane is also mitigated due to the reduced nozzle leakage flow rate, thus the intensity of loading fluctuation on rotor blades is weakened significantly, which is beneficial to improve rotor blade forced response.

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Investigation of Nozzle Clearance Effects on a Radial Turbine: Aerodynamic Performance and Forced Response

Cited by 20 publications

References 10 publications

Understanding of the Interaction between Clearance Leakage Flow and Main Passage Flow in a VGT Turbine

Understanding of the Interaction between Clearance Leakage Flow and Main Passage Flow in a VGT Turbine

Effects of grooved vanes on shock wave and forced response in a turbocharger turbine

A detailed investigation of a variable nozzle turbine with novel forepart rotation guide vane

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