涡轮叶片前缘附近斜射流梯形腔内的流动特性

Flow structure measurement in a trapezoid duct with incline impingement jets near the leading edge

关键词:  叶片前缘  梯形腔  旋流  横流  流动结构  七孔针

Key words:  Leading edge  Trapezoidal duct  Swirl flow  Cross flow  Flow structure  Seven-hole probe

摘要:

涡轮叶片前缘附近内冷腔的几何结构通常较为复杂,建立了梯形内冷通道的放大模型进行实验模拟,考虑复杂流动条件的影响,了解通道内的流动结构与特性,为更高效的内冷通道设计提供参考。使用七孔针对通道流场进行了详细测量,研究射流、横流及气膜孔出流对通道流场的影响规律。结果表明:在射流侧壁面较低位置的射流对靶面的冲击效果良好,较高位置的射流则主要对通道内旋流起到诱导和促进作用,且后者更易受横流影响；通道内横流强度的增加会进一步促进逆时针方向旋流的发展,同时削弱射流的冲击效果；随着射流角度的增加,射流的冲击作用增强,但诱导旋流的能力减弱；气膜出流量和出流位置的改变对通道主体流动结构影响较小。

Abstract:

The internal cooling cavities always had complicated geometry near the leading edge. A simplified trapezoidal duct was built up for experimental research. The primary objective was to visualize the flow structure and flow characteristics in the duct with combined complicated flow conditions. It would provide useful information for the design of highly effective internal cooling system. Experimental measurements were performed using a seven-hole probe. The effect of impingement, cross flow and outflow were considered. Important results of the research include:Impingement jets at high position impinged the target wall effectively, while those at low position contributed to inducing and impelling swirl flow, and the latter were accessible to cross flow influence. The counter-clockwise swirl flow was enhanced with the increasing power of cross flow, but the impingement was deteriorated. At higher impingement angle, the impact effect of the jets was enhanced but swirling strength of the vortex was decreased. The changes of mass flow rate and outflow position of flim cooling holes had no distinct effect on the main flow structure in the passage.