CONJUGATE HEAT TRANSFER CHARACTERISTICS IN A VANE BLADE WITH DIFFERENT DIMPLE/PROTRUSION/PIN FIN CONFIGURATION FOR TRAILING REGION

The high inlet temperature of gas turbine induces high heat load and serious thermal stress problem in the trailing because of the structural and aerodynamic limitations. Thus, it is vital to further improve the cooling performance in the trailing edge area. The configuration with dimple/protrusion/pin fin is proposed to increase the heat transfer and decrease the blade surface temperature in the trailing region. This paper numerically investigated the conjugate heat transfer characteristics in a vane blade with different dimple/protrusion/pin fin configurations for trailing region. There are three different dimple/protrusion locations (in the middle of two rows of pin fin, near the leading edge of each pin fin, a near the trailing edge of each pin fin) and two different dimple/protrusion depth are considered in this paper. The inlet temperature for the hot gas is 1678K, the mass flow ratio of the cooling air is 6.3% of the hot gas. Seven different configurations for the dimple/protrusion/pin fin are involved. The temperature distribution, aerodynamic efficiency and cooling air loss are analyzed. It is found that the configurations of dimple/protrusion/pin fin have significant effect on the temperature distributions and aerodynamics of gas turbine. The pure pin fin configuration has the highest temperature in the trailing region and the pin fin combined with the protrusion configuration has the lowest temperature in the trailing region. The trailing edge temperature can drop up to 20 K after adoption the dimple/protrusion.