气膜出流冷气侧气膜孔附近壁面换热特性

为对纯气膜出流冷气侧气膜孔局部换热特性进行实验研究。取气膜孔前后3倍气膜孔径范围为研究对象。通过改变来流雷诺数、气膜出流与来流流密比以及通道高度与气膜孔径比(小于1范围内),对气膜孔的“溢流效应”进行了研究。研究发现,气膜孔局部的换热均随来流雷诺数、气膜出流与来流流密比的增加而强化,随通道高度与气膜孔径比的增大而降低;孔后的换热要好于孔前的换热,各种通道高度与气膜孔径比下,孔后1倍孔径区域努塞尔数普遍比孔前提高大约20%以上;在气膜孔前后越靠近孔的地方换热越强。

Local heat transfer characteristics near film cooling holes on cooling side in film cooling

Exprimental investigation of local heat transfer characteristics on the cooling side was carried out for the film cooling.The research is focused on upstream and downstream film holes.The investigation about film cooling bleed effect was carried out with different cross flow Reynolds numbers,and different density flow ratios of film outflow to cross flow,and different ratios of the channels height to the film hole diameter.The results indicate that the local heat transfer near the film cooling holes is enhanced with increase of the cross flow Reynolds numbers and density flow ratios of film outflow to cross flow,and weakened with increase of the ratios of the channels height to the film hole diameter.The local heat transfer characteristics downstream the film holes is better than that upstream the film holes,and the average Nu of one diameter area downstream the film holes is generally 20% more than that upstream the film holes.The location closer to the hole has stronger heat transfer whether it is near upstream film cooling holes or downstream holes.