极小尺寸圆形空气射流强化换热的实验研究

摘要

采用极小尺寸喷嘴进行了圆形空气射流的实验研究，测定了在不同雷诺数Re和喷射间距对圆形空气射流冲击换热的影响． 拟合得到了驻点换热的经验公式，并与已有文献结果进行了比较． 实验测量了圆形空气射流换热系数径向分布，得到单调性变化的一般结果；实验还表明在一定的Re和喷射间距下圆形空气射流换热系数径向分布出现层流向湍流过渡．%An extremely small sized round nozzle is used in air jet impingement experiment，from which the effects of Reynolds number and nozzle-to-plate spacing are investigated in detail. The data of stagnation are well correlated with an empirical formula. Also, the local heat transfer coefficients obtained from the experiment show monotonously decreasing with increasing of radial distance from stagnation point. An interesting phenomenon is observed from experimental results that flow boundary layer transition from laminar to turbulence will appear with definite Reynolds number and nozzle-to-plate spacing.