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针对多层涡轮机匣内部典型阵列冲击/气膜,试验研究了横流出流和气膜出流作用对冲击冷却靶面换热系数的综合作用。重点分析了非均匀阵列冲击射流中,冲击雷诺数(6 750~28 500)、横流出流比(0~0.5)等参数对冲击靶板局部和平均努赛尔数的影响。试验中局部和平均努赛尔数均随着冲击雷诺数的增加而提高。当横流出流比增加后,局部和平均努赛尔数均减小。试验结果表明,气膜孔和冲击孔间距较小的工况下能够获得更好的局部换热强化效果。横流出流的存在,削弱冲击射流带来的局部强化冷却作用,并且随着出流比的增大,这种换热削弱程度也逐步变大。
Aiming at the typical array impact / gas film in multi-layer turbine casing, the effects of cross-flow and gas-flow outflow on the heat transfer coefficient of impact cooling target were studied. The influence of some parameters such as impact Reynolds number (6 750 ~ 28 500) and cross-flow outflow ratio (0 ~ 0.5) on the local and average Nusselt number of impact target in non-uniform array impinging jets is analyzed. In the experiment, the local and average Nusselt numbers increase with the impact Reynolds number. When the cross-flow outflow increased, the local and average Nusselt numbers decreased. The experimental results show that the effect of local heat transfer enhancement can be obtained under the condition of small spacing between the film hole and the impact hole. The existence of cross-flow outflow weakens the local intensive cooling caused by impinging jets, and as the outflow ratio increases, the degree of heat-exchange weakening gradually increases.