叶片弦中区内部气膜孔局部换热特性实验

Experimental Investigation of the Local Heat Transfer Characteristics at the Inner Side of the Midchord Region near Film Cooling Holes

对叶片弦中区内部有、无冲击射流的气膜出流冷却方式中,冷气侧气膜孔局部换热特性进行了实验研究。无冲击射流时,主要研究了来流雷诺数、气膜出流与横流密流比的变化对气膜孔局部换热特性的影响;研究发现,气膜孔局部的换热均随两者的增加而强化,且孔后的换热要好于孔前的换热,越靠近孔的地方换热越强,并对倾角为30°和90°时气膜孔的“溢流效应”进行了比较。有冲击射流时,改变冲击雷诺数、横流射流密流比等流动参数,通过对数据整理得出了这些参数对其局部换热特性的影响规律。

Experimental investigation of the turbine blade local heat transfer characteristics at the inner side of the mid-chord region near film holes was conducted, with and without impingement cooling. Under no impingement condition, the investigation was carried out with different crossflow Reynolds Numbers and different density flow ratios of film outflow to cross flow. The research results indicate that the local heat transfer near the film cooling holes is enhanced with the increase of the cross flow Reynolds Numbers and density flow ratios. The local heat transfer characteristics aft the film holes are better than that ahead the film holes. The closer to the holes the stronger heat transfer will be,regardless of ahead or aft the film holes. A compar- ison of extraction effect between 30° and 90° film cooling holes was conducted also. Under the condition with impingement cooling, through the experimental data, effect of flow parameters such as impinging Reynolds Numbers and density flow ratios on the local heat transfer characteristics were obtained.