Experimental Investigation of Effects of Tip Cavity on Tip Clearance Flow in a Variable-Geometry Turbine Cascade
Publication: Journal of Aerospace Engineering
Volume 30, Issue 1
Abstract
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.
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Acknowledgments
This work has been supported by the National Natural Science Foundation of China (Grant Number 51406039) and the Fundamental Research Funds for the Central Universities of China (Number HEUCF150302), which are gratefully acknowledged.
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Published In
Journal of Aerospace Engineering
Volume 30 • Issue 1 • January 2017
Copyright
© 2016 American Society of Civil Engineers.
History
Received: Aug 17, 2015
Accepted: Apr 18, 2016
Published online: Jul 20, 2016
Discussion open until: Dec 20, 2016
Published in print: Jan 1, 2017
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