Measurement and analysis of gas turbine blade endwall heat transfer

Abstract

For many years it has been recognized that the design of an efficient high pressure turbine with adequate component life is crucial to the success of any gas turbine engine project. Inherent in the design process is the need to predict accurately the aerodynamic flow and external heat transfer distribution around the airfoils and end-wall surfaces. A stationary 5 vane linear cascade is designed and developed to investigate gas turbine blade endwall heat transfer and flow. The test cascade is instrumented and calibrated for heat transfer and flow measurement. The vane used in this study is a 2 dimensional model of a first stage gas turbine vane with an endwall profile of an aircraft gas turbine engine. The flow condition in the test cascade corresponds to an overall pressure ratio of 1.08 and an exit Reynolds number based on axial chord of 0.5x10⁶. Static pressure distributions and heat transfer coefficient distributions are measured in the endwall regions without a turbulence grid and with one in the turbulence intensity level of 10.8 %. Detailed heat transfer coefficient distributions are measured by using a transient liquid crystal and the static pressure distributions are measured by using the scani-valve and labview system. Results are shown the P[]/P distribution and heat transfer Nu distribution are seen to increase from the front to the back of the endwall as the flow accelerates. The effect of inlet turbulence intensity is to increase the value of P[]/P and Nu distribution with increasing the size of inlet turbulence intensity.