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对自激励旋进射流冲击冷却的对流换热特性进行了实验研究.通过对旋进射流出口速度进行频谱分析研究其流动特性,结果表明旋进频率显著地受喷嘴尺寸影响,而Strouhal准则数则受喷嘴尺寸和流量的影响都很小.冲击传热实验表明,由于旋进射流对周围流体的卷吸作用使得射流流速显著下降,强化换热效果反而不及普通的冲击射流,而且随喷嘴尺寸的变化,旋进射流与直射射流之间换热性能的差异也没有统一的变化趋势.旋进射流只有在水平外掠加热平板时,才可能获得比普通射流更高的对流换热系数.
The convection heat transfer characteristics of self-excited precessing jet impinging cooling were experimentally studied.The flow characteristics of the precession jet impinging cooling were studied by frequency spectrum analysis.The results show that the precession frequency is significantly affected by the nozzle size, while the Strouhal criterion The impact heat transfer experiments show that due to the entrainment of the entrained jet on the surrounding fluid makes the jet flow rate decreased significantly, the enhanced heat transfer effect but less than the normal impact jet, and with the nozzle size There is also no uniform trend in the variation of the heat transfer performance between the entrained jet and the direct jet.The precession jets may obtain a higher convective heat transfer coefficient than normal jets only when the outer jets are heated horizontally.