涡轮端壁平均气膜冷却效率的正交模拟研究

在涡轮叶栅端壁21%、51%、81%轴向弦长处和距前缘9%轴向弦长端壁处布置4排圆柱形气膜冷却孔,运用CFD方法模拟吹风比、轴向倾角α和展向倾角β3个影响因素共同作用下的端壁平均气膜冷却效率,通过正交方案选出最优孔排布置方式.结果表明:吹风比对端壁平均气膜冷却效率的影响最大,展向倾角β影响次之,轴向倾角α影响最小;吹风比为2.0,轴向倾角α为30°,展向倾角β为45°(第1、第3排冷却孔与y轴负方向成45°,第2、第4排冷却孔与y轴正方向成45°)布置时,端壁表面平均气膜冷却效率最高,为3个因素影响下的最优方案.     

The Effect of Pressure on the Dissociation of H2／CH4 Gas Mixture during Diamond Films Growth via Chemical Vapor Deposition

Monte Carlo simulations are adopted to study the electron motion in mixture of H2 and CH4 duruing diamond synthesis via Glow Plasma-assisted Chemical Vapor Deposition (GPCVD),The non-uniform electric field is used and the avalanche of electrons is taken into account in this simulation.The average energy distribution of electrons and the space distribution of effective species such as CH3,CH3^ ,CH^ and H at various gas pressures are given in this paper,and optimum experimental conditions are inferred from these results.     

涡轮端壁气膜冷却效果数值模拟

采用CFD方法在叶栅端壁21%,51%,81%轴向弦长和前缘上游9%轴向弦长端壁处布置4排圆柱形气膜冷却孔,选用标准κ-ε模型模拟分析端壁单一角度与复合角度射流的冷却效果。结果表明:复合角度射流优势在入射角α=30°时最明显,此时复合角度射流平均冷却效率比单一角度射流平均冷却效率增加16.4%;随着吹风比增加,射流孔附近冷却效率下降速度变慢;复合角度射流的引入会导致反向涡不对称,加强了气膜的贴壁性,更有利于汽膜冷却。