近距离散冲击射流宏观流动品质的研究

STUDY ON FLOW CHARACTERISTICS OF SEPARATED IMPINGEMENT JETS AT SHORT DISTANCE

离散射流宏观流动特性主要是指离散射流的均匀化特性或一排圆射流的二维化进展情况。本文对一排圆射流的自由射流及大空间下的冲击射流宏观流动特性进行了实验研究 ,目的在于确定在近距离散射流冲击下驻点附近小区内流动的不均匀性 ,这种不均匀性有可能导致冷却的不均匀性。

In conventional practice a row of separated circular jets is used in turbine blade or vane for impingement cooling and the relative distance z n/d n is very small ( z n/d n ≤2).In this case,study on longitudinal uniformity of the cooling on the surface of the blade or vane is necessary.In our experiments,the uniformity of the velocity distribution at large relative distance ( z n/d n >10) is achieved by free jet in atmosphere,but the distribution of jet velocity is rapidly uniformized when the jets srtike against the target surface and flow along the surface.The reason of the uniformization is the turbulence mixing and the effect of pressure difference.This work contributes to good understanding for uniformization of cooling on the surface of the blade or vane.