Study On The Film Cooling Characteristics Of The Single Hole With Compound Angle

Most of the jet angles of the films on the turbine components are compound angles.The film cooling characteristics of the compound angle jet are studied to provide data support for the reasonable design of the film hole arrangement.Due to the interaction between blade tip clearance flow and cascade passage flow,the direction of mainstream velocity flowing near the film hole outlet on the turbine component will change periodically.The study of the periodic variation of the mainstream velocity is helpful to understand the internal flow and heat transfer characteristics of the engine.The film cooling mechanism of the single hole compound angle was studied by the steady numerical simulation method.The film cooling characteristics were mainly analyzed as the blowing ratio was 0.5,0.8,1.1 and 1.4,the jet angle ? = 30°,60° and 90° and the azimuth angle ? = 45° and 90°.The results show that after the coolant jet ejected from the film hole,it will be detached from the wall and then attached again,and the existence of azimuth angle structure weakens this phenomenon.From the whole region,the cooling effect of azimuth ? = 45° is the best.The unsteady numerical simulation method was used to study the influence of the mainstream oscillation on the film cooling.The film cooling characteristics were mainly analyzed as the blowing ratio was 0.5,0.8,1.1 and 1.4,and the oscillation frequency f = 100 Hz,160 Hz and 220 Hz.The results show that the distribution of film cooling effectiveness is affected by both the blowing ratio and the mainstream oscillate frequency.The mainstream oscillate greatly improves the film cooling effect.The film cooling effectiveness is affected by the mainstream oscillate frequency obviously at the high blowing ratio.At the blowing ratio of 0.5,the time-averaged film cooling effectiveness in the spanwise direction decreased by about 80%,68% and 61% as the mainstream oscillate frequency f= 100 Hz,160 Hz and 220 Hz,respectively.At the blowing ratio of 1.4,the time-averaged film cooling effectiveness in the spanwise direction increases gradually along the positive direction of the X-axis.The time-averaged film cooling effectiveness in the spanwise direction increased by about 576.6%,781.9% and 926.4% as the mainstream oscillate frequency f= 100 Hz,160 Hz and 220 Hz,respectively.At the same blowing ratio,the higher mainstream oscillation frequency lead to the better film cooling effect and the greater enhancement ratio.