Effects of ultrasonic waves on subcooled pool boiling on a small plain heating surface
Effects of ultrasonic waves on subcooled pool boiling on a small plain heating surface
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超声波对小平面受热面过冷池沸腾的影响
DOI：
10.1016/j.ces.2019.03.009
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发表时间：
2019
影响因子：
4.7
通讯作者：
Yang Kai
中科院分区：
文献类型：
--
作者：
Tang Jiguo;Sun Licheng;Wu Dan;Du Min;Xie Guo;Yang Kai
通过实验研究了超声波对小平面受热面过冷池沸腾的影响。采用不同幅度(0~10 μm)的超声波对核态沸腾和过渡态沸腾进行处理，液体过冷度和热流密度分别为15~60 K和0.15~8 mW/m2。结果表明，在低热流密度下，高振幅超声诱导的声流对核态沸腾有明显的强化作用，但随着热流密度的增加和超声幅值的减小，这种强化作用将受到限制。在过渡沸腾区域，超声波产生不同的影响。当液体过冷度为15 K时，微气泡发射沸腾不会正常发生，强烈的声流激发微气泡发射沸腾，从而显著强化换热。过冷度为21~40 K时，过渡沸腾为稳定的微平衡沸腾，超声对换热和气泡行为影响不大。当过冷度增加到50~60 K时，10 μm幅值的超声对微通道的换热有增强作用，而5 μm的幅值的超声则使换热变差。相反的结果取决于超声波对受热面上汽膜坍塌和振荡的不同影响。
Experiments were conducted to investigate the effects of ultrasonic waves on subcooled pool boiling on a small plain heating surface. Ultrasonic waves with different amplitudes (0–10 μm) were applied for both nucleate boiling and transition boiling modes with the liquid subcooling and heat flux covering 15–60 K and 0.15–8 MW/m2, respectively. The results show that the acoustic streaming induced by high amplitude ultrasound has an obvious enhancement effect on nucleate boiling at low heat flux, but the augmentation will be restricted with increase in heat flux and decrease in ultrasonic amplitude. In transition boiling region, the ultrasound makes different impact. At liquid subcooling of 15 K under which microbubble emission boiling (MEB) would not occur normally, the strong acoustic streaming triggers MEB, thereby heat transfer is significantly enhanced. At subcooling of 21–40 K, the transition boiling is in the mode of stable MEB, the ultrasound barely affects the heat transfer and bubble behaviors. With the subcooling increasing to 50–60 K, the heat transfer of MEB is enhanced by the 10 μm amplitude ultrasound but deteriorated by the 5 μm amplitude ultrasound. The opposite results depend on the different effects arising from the ultrasound on the collapse and oscillation of the vapor film on the heating surface.