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ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2016, Vol. 37 ›› Issue (12): 3615-3624.doi: 10.7527/S1000-6893.2016.0139

• Fluid Mechanics and Flight Mechanics • Previous Articles     Next Articles

Aerodynamic performance of a variable geometry turbine cascade using a vane-end winglet

GAO Jie, ZHENG Qun, LIU Pengfei, WEI Ming   

  1. College of Power and Energy Engineering, Harbin Engineering University, Harbin 150001, China
  • Received:2015-12-17 Revised:2016-04-29 Online:2016-12-15 Published:2016-05-04
  • Supported by:

    National Natural Science Foundation of China (51406039); Natural Science Foundation of Heilongjiang Province of China (QC2016059)

Abstract:

In a high endwall-angle variable-geometry turbine, the rotating shaft end can lead to a serious deterioration of endwall flow fields when the variable vane rotates. A winglet is proposed to be applied to the variable vane casing-end to overcome this problem and then reduce the vane-end leakage flow. Combined with the low-speed wind tunnel test, numerical investigation is performed by solving Reynolds-averaged Navier-Stokes equations in conjunction with a standard k-ω two-equation turbulence model. The endwall flow fields and loss distribution of the variable vane with winglets are analyzed. The effects of vane turning are discussed. The vane-end cavity-winglet structure is then proposed, and the aerodynamic performance and its sensitivity to vane-end clearance height are evaluated. The results show that the variable vane with winglets can not only avoid the deterioration of endwall flow fields caused by vane turning, but also reduce the vane-end clearance leakage driving force, thus leading to improved endwall flow performance of variable vanes at all turning angles. Besides, the variable vane with cavity-winglets can further reduce the leakage flow, and the total pressure loss coefficient is reduced overall by 8.9% as compared to the baseline.

Key words: variable geometry turbine, winglet tip, cavity tip, aerodynamic loss, cascade

CLC Number: