多斜孔截面面积变化对孔内流动与换热特性的影响

Influence of Flow and Heat Transfer Characteristics to Inclined Multi Holes Section Area Change in Holes

对多斜孔内部流通截面面积进行了对比分析,设计了5种流通面积沿程变化模型,分别为不变(圆柱型)、逐渐减小(渐缩圆台形)、先增大后减小(外凸形)、先减小后增大(内凹形)、逐渐增大(渐扩圆台形)。通过数值模拟研究了其对斜孔内流动与换热特性的影响。结果表明:多斜孔内部流通截面的变化使得其孔内气流压力、流动以及微团流动规律发生显著变化;在截面积由渐缩变为渐扩的过程中,流体微团在出口处转动方向由顺时针转为逆时针;流通面积的扩大使得压力沿程逐渐降低,在多斜孔出口下游形成低压区,出口气膜附壁性增强,气膜冷却效果增强;在多斜孔内,流通面积的扩大使得斜孔内壁背风面压力较大、流速较大、对流换热较强,斜孔内壁迎风面流体脱壁,换热较弱。

Five effusion cooled Plates in which the cross-sectional area of the hole continuously changed（ circle,taPered cone,convex outside,concave inside and divergent cone）were designed to study the flow and heat transfer characteristics in the hole. The results show that the change of the＆amp;nbsp;cross-sectional area in the effusion hole leads to the corresPonding changes of Pressure and the flow characteristic of fluid element in the hole. With the flow area in the hole changes from taPer into di-vergence,the rotation direction of fluid element changes from clockwise to counterclockwise at the ex-it,the exPansion of flow area makes the Pressure lower along,and the Pressure on the lower reaches of the exit is low,which enhances the Coanda effect and film cooling effectiveness. The Pressure on leeward side of the effusion hole is larger,and the cooling effect is better,while on the windward side,the fluid takes off the wall,the Pressure is lower and the cooling effect is worse.