离散气膜孔下游边界层的实验研究

 “Ｘ”型热线测量了离散气膜孔下游边界层内的湍流量,将热线探头绕轴转三个角方位以感受三维湍流场信息。结果表明,边界层内湍动能分布呈反“Ｓ”形,吹风比和孔排数对参数分布有重要影响,这种影响在很长距离上不消失,所以,常用的ｋ－ε模型不经修正不能正确预计这类边界层的发展。

AN EXPERIMENTAL INVESTIGATIOM OF BOUNDARY LAYERS DOWNSTREAM OF DISRETE FILM COOLING HOLES

An″X″type hot wire probe was used to measure the turbulent parameters,such as turbulent kinetic energy and turbulent stress,in boundary layers downstream of discrete film cooling holes.The probe was rotated to three orientations on its axis in order to obtain plenty information of three dimensional flow. From experimental data it is indicated that the profiles of turbulence kinetic energy in boundary layer appeared with the shape of a reversed.The blowing ratio and the number of film cooling hole rows gave significant influence on the profiles which remained in a long distance downstream. Therefore,the commonly used k-ε turbulence model could not be applied to predict this kind of boundary layer successfully without modification.