双向扩张型孔射流角度对气膜冷却特性影响的实验

设计了气膜冷却实验台,测量了单排7个气膜孔的平均换热系数和冷却效率.气膜孔倾角为20°,45°和90°,孔间距P/d=3.动量比变化范围为1～4.重点研究主流零压力梯度下动量比和孔倾角对换热系数比和冷却效率影响.结果表明,动量比的增加使换热系数比和冷却效率都增加,随着倾角增加,动量比对冷却效率的影响减弱;倾角对换热系数比的影响非常复杂,倾角的增加使冷却效率减小.倾角20°的冷却效率明显高于倾角45°和90°的冷却效率. 

Experimental investigation on film cooling of expanded hole at both inlet and outlet with various injection angles

Abstract: For the purpose of studying film cooling characteristics of expanded holes, heat transfer coefficient ratios and film cooling effectiveness is investigated downstream of a row of holes with inclination angles of 20° 45° and 90° with three hole diameters apart. Momentum flux ratios vary in the range of 1 to 4. The discussion is focused on the effect of momentum flux ratios and inclination angles on heat transfer coefficient ratios and film cooling effectiveness in the presence of mainstream zero pressure gradient. The experimental results show that the increasing momentum flux ratios leads to the increasing heat transfer coefficient ratios and film cooling effectiveness. The effect of momentum flux ratios on cooling effectiveness becomes weaker with the increasing angles. The angles have complex influence on heat transfer coefficient ratios. The increasing angles leads to the decreased cooling effectiveness.Film cooling effectiveness of inclination angle of 20° is bigger than those of 45° and 90°.