Study on the Interaction of Clearance Flow and Shock Wave in a Turbine Nozzle

Lei, Xinguo; Qi, Mingxu; Sun, Harold; Shi, Xiuyong; Hu, Liangjun

doi:10.4271/2017-01-1039

Cited by 7 publications

(4 citation statements)

References 7 publications

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“…More detailed information about the test rig and validations of numerical simulations can be found in prior publications. 20,21…”

Section: Resultsmentioning

confidence: 99%

“…More detailed information about the test rig and validations of numerical simulations can be found in prior publications. 20,21 Figure 13 also shows the flow characteristics of a shock wave and the leakage flow from the linear nozzle turbine vanes captured by the Schlieren photography system. It is fairly clear that the shock wave originates near the nozzle vane trailing edge and the nozzle endwall clearance leakage flow gradually drifts away from the nozzle vane during flowing downstream.…”

Section: Experimental Validationmentioning

confidence: 99%

See 1 more Smart Citation

Variable nozzle turbocharger turbine performance improvement and shock wave alternation by distributing nozzle endwall clearances

Zhao

Sun

et al. 2018

Proceedings of the Institution of Mechanical Engineers, Part D:

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Effects of nozzle endwall clearances on variable nozzle turbocharger turbine performances have been widely studied, but improving the variable nozzle turbocharger efficiency utilizing an optimal distribution of nozzle endwall clearances between the hub and the shroud sides has not drawn wide attention. Meanwhile, with the various distributions, shock wave variations that are closely related to turbine reliability are rarely reported. To fill the gap, this research performed three-dimensional numerical simulations on a variable nozzle turbocharger turbine to analyze the effects of various nozzle endwall clearance distributions on both turbine performance and shock wave. The results showed that there is an optimal distribution of the nozzle endwall clearance that can improve turbine efficiency and shift nozzle trailing edge shock wave. Performed on a linear turbine nozzle and with detailed validations, both experimental measurements and numerical simulations provide evidence that supports the numerical analyses conducted on a variable nozzle turbocharger turbine.

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“…More detailed information about the test rig and validations of numerical simulations can be found in prior publications. 20,21…”

Section: Resultsmentioning

confidence: 99%

Section: Experimental Validationmentioning

confidence: 99%

Variable nozzle turbocharger turbine performance improvement and shock wave alternation by distributing nozzle endwall clearances

Zhao

Sun

et al. 2018

Proceedings of the Institution of Mechanical Engineers, Part D:

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show abstract

“…Nevertheless, under certain operational conditions, the area formed by the vanes is reduced to increase the velocity of the exhaust gases entering the rotor [8] and resulting in high Mach numbers and the development of shock waves in the stator [9]. This evidence has been portrayed in some papers where the behavior of the shock waves is studied, as in [10,11]. The location of the shock waves depends on the blade geometry , appearing in the throat formed between the vanes or on the suction side (SS) of the vanes.…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis of the Effects of Grooved Stator Vanes in a Radial Turbine Operating at High Pressure Ratios Reaching Choked Flow

et al. 2023

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The flow through the stator vanes of a variable geometry turbocharger turbine can reach supersonic conditions and generates a shock wave on the stator vanes, which has a potential impact on the flow loss as well as on unsteady aerodynamic interaction. The shock wave causes a sudden increase in pressure and can lead to boundary separation and strong excitation force, besides pressure fluctuation in the rotor blades. Thus, in this study, the flat surface of the vanes of a commercial variable geometry turbocharger turbine has been modified to analyze the effects of two grooved surfaces configuration using CFD simulations. The results reveal that the grooves change the turbine efficiency, especially at higher speed, where the increase in the efficiency is between 2% and 6% points. Additionally, the load fluctuation around the rotor leading edge can be reduced and minimize the factors that compromise the integrity of the turbine. Furthermore, the grooves reduce the supersonic pocket developed on the suction side of the vane and diminish the shock wake intensity. Evaluating the effectiveness of the available energy usage in the turbine, on the one hand, at lower speed, the fraction of energy at the inlet destinated to produce power does not change significantly with a grooved surface on the stator vanes. On the other hand, at higher speed and higher pressure ratio with 5 grooves occurs the most effective approach of the maximum energy.

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“…With the aim of improving the reliability of a radial inflow turbine with nozzle vanes, a method of using a grooved surface on the nozzle vanes was proposed by Sun et al, 11 and, subsequently, more detailed analyses were reported in previous studies. 12–15 Following the previous research work, this article investigated the forced response of a turbine wheel by the coupled method of the computational fluid dynamics (CFD) simulations and the finite element analysis (FEA) calculations.…”

Section: Introductionmentioning

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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Study on the Interaction of Clearance Flow and Shock Wave in a Turbine Nozzle

Cited by 7 publications

References 7 publications

Variable nozzle turbocharger turbine performance improvement and shock wave alternation by distributing nozzle endwall clearances

Variable nozzle turbocharger turbine performance improvement and shock wave alternation by distributing nozzle endwall clearances

Numerical Analysis of the Effects of Grooved Stator Vanes in a Radial Turbine Operating at High Pressure Ratios Reaching Choked Flow

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

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