The Effects of Inclination Angle on the Cooling Performance of Fan-Shaped Holes under Different Blowing Ratios

Film cooling technology is widely adopted in aero-engine to lower the temperature of hot components such as combustor liner and turbine blade. Compared with a conventional cylindrical hole, a fan-shaped hole is expected to be more advantageous with higher film cooling effectiveness. To gain a further understanding of the influence of the inclination angle on the film cooling effectiveness, the cooling performance of a multi-perforated plate with fan-shaped holes is numerically investigated. In particular, inclination angles from 20° to 30° are addressed at five blowing ratios ranging from 0.5 to 7.5. The results show that the film cooling effectiveness is barely influenced by inclination angle at low blowing ratio (BR=0.5), while it varies dramatically at high blowing ratios (BR≥1.5). It is noted that a much better cooling performance occurs at inclination angle around 25° due to improved lateral spreading of the coolant, especially at high blowing ratios. Furthermore, the film cooling effectiveness is significantly affected by blowing ratio when it changes from 0.5 to 1.5, however, no evident variation is detected with blowing ratios increasing from 1.5 to 7.5.