Influence of Shock Wave on Loss and Breakdown of Tip-Leakage Vortex in Turbine Rotor with Varying Backpressure
In modern turbine rotors, tip-leakage flow is a common phenomenon that accounts for about 1/3 of the stage loss. Studies show that as the imposed load increases, a shock wave appears in the tip region, which causes a significant interference on the leakage vortex. In the present study, numerical sim...
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doaj-5b30a34eeb64499d91a0aad9aa9fc56d2021-06-01T01:30:00ZengMDPI AGApplied Sciences2076-34172021-05-01114991499110.3390/app11114991Influence of Shock Wave on Loss and Breakdown of Tip-Leakage Vortex in Turbine Rotor with Varying BackpressureZuojun Wei0Guangming Ren1Xiaohua Gan2Ming Ni3Weijie Chen4Department of Mechanics and Aerospace Engineering, Southern University of Science and Technology, Shenzhen 518055, ChinaDepartment of Mechanics and Aerospace Engineering, Southern University of Science and Technology, Shenzhen 518055, ChinaDepartment of Mechanics and Aerospace Engineering, Southern University of Science and Technology, Shenzhen 518055, ChinaDepartment of Mechanics and Aerospace Engineering, Southern University of Science and Technology, Shenzhen 518055, ChinaTurbomachinery Aerodynamics and Acoustics Lab (TAAL), School of Power and Energy, Northwestern Polytechnical University, Xi’an 710072, ChinaIn modern turbine rotors, tip-leakage flow is a common phenomenon that accounts for about 1/3 of the stage loss. Studies show that as the imposed load increases, a shock wave appears in the tip region, which causes a significant interference on the leakage vortex. In the present study, numerical simulations are carried out to investigate the influence of the shock wave on the loss and breakdown of the tip-leakage vortex. The obtained results indicate that with no effective control on the flow, the loss of the leakage vortex has an approximate exponential growth up to about 10 times as the outlet Mach number increases from 0.67 to 1.15 and the corresponding proportion in the total loss increases sharply to 30.2%. It is found that the stagnation position of the breakdown changes with the backpressure and the amplitude of variation along the axial direction is up to 0.13 <i>C</i><sub>x</sub>. It is inferred that the breakdown of the leakage vortex core may be affected by the periodical passing of downstream blade and the induced pressure fluctuation may result in additional vibration in this rotor blade. The leakage vortex is unstable in supersonic flow with a shock wave and it may transfer to a flow with a low-velocity bubble in its core region. It is concluded that the leakage vortex breakdown mainly originates from interferences of the shock wave, while the internal cause of such breakdown is the centrifugal instability of the vortex.https://www.mdpi.com/2076-3417/11/11/4991tip-leakage lossvortex breakdownshock wave/vortex interactionvortex instability |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Zuojun Wei Guangming Ren Xiaohua Gan Ming Ni Weijie Chen |
spellingShingle |
Zuojun Wei Guangming Ren Xiaohua Gan Ming Ni Weijie Chen Influence of Shock Wave on Loss and Breakdown of Tip-Leakage Vortex in Turbine Rotor with Varying Backpressure Applied Sciences tip-leakage loss vortex breakdown shock wave/vortex interaction vortex instability |
author_facet |
Zuojun Wei Guangming Ren Xiaohua Gan Ming Ni Weijie Chen |
author_sort |
Zuojun Wei |
title |
Influence of Shock Wave on Loss and Breakdown of Tip-Leakage Vortex in Turbine Rotor with Varying Backpressure |
title_short |
Influence of Shock Wave on Loss and Breakdown of Tip-Leakage Vortex in Turbine Rotor with Varying Backpressure |
title_full |
Influence of Shock Wave on Loss and Breakdown of Tip-Leakage Vortex in Turbine Rotor with Varying Backpressure |
title_fullStr |
Influence of Shock Wave on Loss and Breakdown of Tip-Leakage Vortex in Turbine Rotor with Varying Backpressure |
title_full_unstemmed |
Influence of Shock Wave on Loss and Breakdown of Tip-Leakage Vortex in Turbine Rotor with Varying Backpressure |
title_sort |
influence of shock wave on loss and breakdown of tip-leakage vortex in turbine rotor with varying backpressure |
publisher |
MDPI AG |
series |
Applied Sciences |
issn |
2076-3417 |
publishDate |
2021-05-01 |
description |
In modern turbine rotors, tip-leakage flow is a common phenomenon that accounts for about 1/3 of the stage loss. Studies show that as the imposed load increases, a shock wave appears in the tip region, which causes a significant interference on the leakage vortex. In the present study, numerical simulations are carried out to investigate the influence of the shock wave on the loss and breakdown of the tip-leakage vortex. The obtained results indicate that with no effective control on the flow, the loss of the leakage vortex has an approximate exponential growth up to about 10 times as the outlet Mach number increases from 0.67 to 1.15 and the corresponding proportion in the total loss increases sharply to 30.2%. It is found that the stagnation position of the breakdown changes with the backpressure and the amplitude of variation along the axial direction is up to 0.13 <i>C</i><sub>x</sub>. It is inferred that the breakdown of the leakage vortex core may be affected by the periodical passing of downstream blade and the induced pressure fluctuation may result in additional vibration in this rotor blade. The leakage vortex is unstable in supersonic flow with a shock wave and it may transfer to a flow with a low-velocity bubble in its core region. It is concluded that the leakage vortex breakdown mainly originates from interferences of the shock wave, while the internal cause of such breakdown is the centrifugal instability of the vortex. |
topic |
tip-leakage loss vortex breakdown shock wave/vortex interaction vortex instability |
url |
https://www.mdpi.com/2076-3417/11/11/4991 |
work_keys_str_mv |
AT zuojunwei influenceofshockwaveonlossandbreakdownoftipleakagevortexinturbinerotorwithvaryingbackpressure AT guangmingren influenceofshockwaveonlossandbreakdownoftipleakagevortexinturbinerotorwithvaryingbackpressure AT xiaohuagan influenceofshockwaveonlossandbreakdownoftipleakagevortexinturbinerotorwithvaryingbackpressure AT mingni influenceofshockwaveonlossandbreakdownoftipleakagevortexinturbinerotorwithvaryingbackpressure AT weijiechen influenceofshockwaveonlossandbreakdownoftipleakagevortexinturbinerotorwithvaryingbackpressure |
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