Effects of cylindrical hole accompanied with anti-vortex holes on film cooling effectiveness
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摘要: 采用数值模拟方法研究了大小气膜孔交替排列(均匀排列的圆柱形单孔两侧分别开设一个平行的小孔)情况下的流动和换热,并与常规的圆柱形单孔结构进行对比,分析大小气膜孔交替排列提高冷效的机理,研究大小孔的孔径比对气膜冷却效果的影响规律.结果发现:在圆柱形单孔两侧分别设置一个平行的辅助小孔,大小孔冷气射流的肾形涡相互干涉,导致主气膜孔下游的肾形涡的尺度和强度与圆柱形单孔相比均有明显降低,气膜冷却效果明显改善.相同冷气量下,小孔孔径越大,分配的冷气流量越大,对主孔冷气射流的干涉作用越强,气膜冷却效果改善越明显;当小孔孔径d2=4mm时,气膜冷却结构类似常规的离散圆柱形气膜孔,气膜冷却效果开始下降.Abstract: The primary focus was to further understand the flow and heat transfer aspects of a special film cooling hole arrangement where the main film cooling hole was accompanied by two parallel anti-vortex jet holes. The cooling effectiveness and the interaction between the main hot stream and the coolant jets were simulated and compared with the standard single hole arrangement. It is found that the presence of anti-vortex jets decreased the size and the strength of the counter-rotating vortex pair of the main coolant jet and so is its mixing with the main hot stream. The surface film effectiveness value is improved as expected. A bigger diameter of anti-vortex holes means more obvious improvement of film cooling.
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Key words:
- film cooling /
- adiabatic effectiveness /
- jet /
- counter-rotating vortex pair
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