Aerothermodynamics

Experimental Investigation of Aerodynamic Performance due to Blade Tip Clearance in a Gas Turbine Rotor Cascade

  • CHUNG Jinmoo ,
  • BAEK Seungchan ,
  • HWANG Wontae
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  • 1. Department of Mechanical Engineering, Seoul National University, Seoul 08826, Republic of Korea
    2. Institute of Advanced Machines and Design, Seoul National University, Seoul 08826, Republic of Korea 
    3. Institute of Engineering Research, Seoul National University, Seoul 08826, Republic of Korea

Online published: 2023-11-30

Copyright

Science Press, Institute of Engineering Thermophysics, CAS and Springer-Verlag GmbH Germany, part of Springer Nature 2022

Abstract

This study examines how the complex flow structure within a gas turbine rotor affects aerodynamic loss. An unshrouded linear turbine cascade was built, and velocity and pressure fields were measured using a 5-hole probe. In order to elucidate the effect of tip clearance, the overall aerodynamic loss was evaluated by varying the tip clearance and examining the total pressure field for each case. The tip clearance was varied from 0% to 4.2% of blade span and the chord length based Reynolds number was fixed at 2×105. For the case without tip clearance, a wake downstream of the blade trailing edge is observed, along with hub and tip passage vortices. These flow structures result in profile loss at the center of the blade span, and passage vortex related losses towards the hub and tip. As the tip clearance increases, a tip leakage vortex is formed, and it becomes stronger and eventually alters the tip passage vortex. Because of the interference of the secondary tip leakage flow with the main flow, the streamwise velocity decreases while the total pressure loss increases significantly by tenfold in the last 30% blade span region towards the tip for the 4.2% tip clearance case. It was additionally observed that the overall aerodynamic loss increases linearly with tip clearance.

Cite this article

CHUNG Jinmoo , BAEK Seungchan , HWANG Wontae . Experimental Investigation of Aerodynamic Performance due to Blade Tip Clearance in a Gas Turbine Rotor Cascade[J]. Journal of Thermal Science, 2022 , 31(1) : 173 -178 . DOI: 10.1007/s11630-022-1554-4

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