Heat Transfer and Secondary Flow with a Multicavity Gas Turbine Blade Tip

Abstract

Multicavity gas turbine blade tips were formed by adding ribs in the blade tip cavities of squealer tips, and the effects of the tip clearance size, the number and the installation angle of the ribs on the tip heat transfer, and the blade passage total pressure loss were investigated experimentally. Tests were conducted in a low-speed linear cascade. The transient liquid crystal technique and a seven-hole probe were used to measure the heat transfer and flowfield, respectively. Results showed that a multicavity tip was able to reduce the total pressure loss coefficient, and the total pressure loss coefficients decreased as the number of ribs increased. Additional ribs on the tip cavity reduced the heat transfer coefficients on the cavity surface near the leading edge, but induced an additional high heat transfer coefficient region downstream from the rib due to the flow reattachment.