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摘要
A series of numerical simulations are performed to study the internal crossflow effect on single-row film cooling performances on a turbine blade suction surface, under the representative film-cooled engine-simulated conditions. The cylindrical and fan-shaped holes are considered, both having the same length-to-diameter of 3. In the current simulations, the blowing ratio (Br) is selected as 1, 2 and 3 respectively. The velocity ratio of the internal crossflow to ejection jet (Vr) is selected as 0, 1 and 2, respectively. The results show that the helical flow feature is dominant inside film hole with the presence of internal crossflow and the ejection jet is pushed toward one side in accordance to the internal flow direction. For the fan-shaped hole, the effect of internal crossflow on mutual interaction between ejection jet and primary flow downstream the film cooling hole is relatively weaker in compared to the cylindrical hole. In general, the velocity ratio of Vr=1.0 has a little influence on the film-hole discharge coefficient. However, under a high velocity ratio of Vr=2.0, approximately 15%similar to 20% reduction of discharge coefficient is produced for the cylindrical hole, and 20%similar to 27% reduction for the fan-shaped hole. In the viewing of laterally-averaged adiabatic film cooling effectiveness, the impact of internal crossflow effect is more profound for the cylindrical hole. In general, a moderate velocity ratio (Vr=1.0) plays a positive role on film cooling improvement but a high velocity ratio (Vr=2.0) is confirmed to reduce the film cooling effectiveness.
- 出版日期2018
- 单位南京航空航天大学
