Large-eddy simulation of single-row serrated trenched-hole film cooling on turbine guide vane

Abstract

Large-eddy simulations were conducted to study the film cooling characteristics of a serrated trenched-hole cooling geometry on a scaled turbine guide vane. The simulations were carried out under a blowing ratio of M = 2.0. The serrated trench was placed on the suction and pressure side, respectively. The results show that the mainflow environment above the suction side differs from that above the pressure side. Therefore the adiabatic film cooling effectiveness changes correspondingly. Within the range of x/d = 3 to x/d = 25, the are-averaged adiabatic film cooling effectiveness on the pressure side is about 21% higher than that on the suction side. By presenting the vortex structure and unstable statistic results of the trenched-hole region and downstream flow field, the present study analyses in detail the characteristics of the coolant flow patterns and the coolant-mainflow interaction at both the suction and pressure side. Results show that the cooling jet penetration is suppressed on the suction side, while the intense mainflow entrainment results in dramatic destruction of the cooling film protection. Unlike the situation at the suction side, although coolant penetration is more substantial on the pressure side, film cooling shows good performance due to the unstable concave flow.