单孔复合角气膜冷却的流动与传热的实验研究

EXPERIMENTAL INVESTIGATION ON FLOW AND HEAT TRANSFER AROUND SINGLE FILM COOLING HOLE WITH COMPOUND-ANGLE

关键词:  薄膜冷却  涡轮部件  温度分布  流动分布  试验

Key words:  Film cooling  Turbine part  Temperature distribution  Flow distribution  Test

摘要:

在吹风比Ｍ＝１．０和２．０的工况下，分别用五孔针和热电偶测量了流向倾角α为３０°和６０°、侧向倾角β为３０°和４５°以及喷孔出口扇形角γ为０°和３０°的复合角气膜冷却的流场和温度场，首次在实验中发现复合角射流下游存在一强一弱反向旋转的纵向耦合涡结构，其流向速度Ｕ／Ｕ∞和无因次温度θ的等值线均呈不对称腰子形。α、β、γ以及Ｍ的变化均将对流场和温度场产生影响。扇形孔射流具有较宽的气膜覆盖区域，能够有效地降低旋涡强度，具有比圆孔高得多的冷却效率。

Abstract:

xperimental results describe the effects of blowing ratio at M=1. 0 and 2. 0, injection angles on flow field and heat transefer in the downstream of single film cooling hole with compoundangle orientations. The hole with a fan-shaped angle of 0°or 30° was oriented so that its angles with respet to the test surface are 30°or 60°in a stream/normal plane projection, and 30°or 45°in a spanwise/normal plane projection. The measurements were carried out with a detailed directional fivehole probe and thermocouple surveys of the three-dimensional flow field and surface heat transfer distribution. For the first time, it is found in experiments that a pair of counterrotating vorticesone is strong and another is weak, was observed in the downstream region of jet exit. Contours of longitudinal velocity U/U∞ and non-dimensional temperature θ show asymmetric kidney shape. The flared hole effectively decreases the strength of longitudinal vortex and increases the spreading of jet so that the film cooling effectiveness would be much greater than that found in the downstream of circular hole.