孔阵排列疏密度对致密多孔壁冷却效果的影响

Effect of porosity of holes array on cooling effectiveness of effusion cooling

关键词:  航空发动机  疏密度+  致密多孔壁冷却+  薄膜冷却

Key words:  Aircraft engine  Porosity~+  Effusion cooling~+  Film cooling

摘要:

为了获得气膜孔阵排列的疏密度对致密多孔壁冷却效果的影响规律, 分别对四种疏密度排列下的平板热侧面上的冷却效果进行了数值模拟研究。各物理模型通过改变气膜孔径大小和孔间距得到不同的孔阵排列疏密度。为了便于相互比较, 各计算模型的边界条件完全相同, 而且平板气膜孔区单位面积上冷气流量均相等。计算结果显示: 在一定的范围内, 孔阵排列的疏密度越大, 冷却效果越好。在热侧面上的气膜孔区及其下游区, 致密多孔壁的冷却效果都非常好, 比同等条件下常规气膜冷却的效果好得多。

Abstract:

To investigate the influence of porosity of holes array on cooling effectiveness of an effusion cooled plat plate, a numerical study of the distributions of cooling effectiveness on the hot side of an effusion cooled flat plate was carried out with four different porosities of holes array. The required porosities for various cases were obtained through varying the diameter of holes and spacing among the holes. For all the four cases the boundary conditions are exactly the same and the coolant mass flux per unit area in the region with holes on the plate is also the same. The computational results show that to a certain extent the denser of the distribution of the holes, the higher of the cooling effectiveness.The cooling effectiveness of effusion cooling in the regions with holes and downstream the last row of holes on hot side is much higher than that of conventionary film cooling with the same operation conditions.