Turbine vane endwall partition film cooling based on the passage vortex core line

Abstract

The aerodynamic and cooling characteristics of the endwall were studied by numerical and experimental methods. Two film-hole configurations, i.e. conventional film-hole arrangement and partitioned film-hole arrangement, were taken into consideration. The partitioned film-hole arrangement is proposed based on the analysis of the heat load and the near wall flow field of the endwall. The results show that the high heat transfer coefficient region on the endwall pressure side is consistent with the passage vortex core line, but independent of the pressure side separation line of the horseshoe vortex. Accordingly, the endwall is divided into five regions based on the suction side separation line of the horseshoe vortex and the passage vortex core line. The five regions include upstream-passage wedge region, leading edge region, pressure side region, downstream region of the pressure side and downstream region of the suction side. Compared with the conventional film-hole arrangement, the partitioned film-hole arrangement weakens the mixing of the coolant jet and the mainstream, thus reducing the energy loss and the total pressure loss at the outlet of the cascade. More importantly, the partitioned film-hole arrangement provides much uniform film coverage and a significant increase of the area-averaged film-cooling effectiveness by using less cooling air. This is derived from the fact that the partitioned film-hole arrangement has more film holes in the pressure side of the endwall with high back pressure, which improves the distribution of coolant on the endwall.