Experimental Investigation of Effects of Tip Cavity on Tip Clearance Flow in a Variable-Geometry Turbine Cascade

The variable-geometry turbine is often used to improve the gas turbine part-load performances; however, there are performance penalties associated with the vane-end part clearance that is required for the smooth movement of variable-geometry vanes. To determine the effects of tip cavity on tip clearance flows in a variable-geometry vane, experimental investigations with a variable-geometry turbine linear cascade have been conducted. The tip-cavity effects on the overtip-leakage flow and losses, and the effects of turning angle on the total pressure losses and the yaw angle are considered. The measurement results show that the variation of vane-turning angles completely changes the vane-loading distribution. As the vane-turning angle varies from design to closed, the vane loading increases and tends to be more aft loaded, thus increasing the tip-leakage loss, and vice versa. At all turning angles, the tip-leakage vortex is weakened by the tip cavity, and the cavity tip plays a significant role in reducing aerodynamic losses. The results can provide guidelines for the vane-end clearance control of variable-geometry turbines.

Language

  • English

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Filing Info

  • Accession Number: 01611328
  • Record Type: Publication
  • Files: TRIS, ASCE
  • Created Date: Jul 20 2016 3:01PM