Experimental study of sound emission in subcooled pool boiling on a small heating surface
Experimental study of sound emission in subcooled pool boiling on a small heating surface
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小受热面过冷池沸腾声发射实验研究
DOI：
10.1016/j.ces.2018.05.002
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发表时间：
2018
影响因子：
4.7
通讯作者：
Du Min
中科院分区：
文献类型：
--
作者：
Tang Jiguo;Xie Guo;Bao Jingjing;Mo Zhengyu;Liu Hongtao;Du Min
本文对小板式加热器过冷池沸腾的声发射进行了实验研究。使用水听器记录声信号，并使用声压级(SPL)、快速傅立叶变换和离散小波变换(DWT)进行分析。结果表明，SPL结合离散小波变换对声信号的分析，可用于沸腾模式的识别和强化换热。与大型板式加热器或长丝加热炉不同，核态沸腾区域的SPL与壁面过热度的关系曲线呈“N”字形。可视化结果表明，这种差异主要源于加热器尺寸对气泡生长和脱离的影响。与核态沸腾相比，在微泡发射沸腾区域，液固比呈现阶跃增加10-20 分贝，并随着热流密度的进一步增加而继续增大。对气泡频率和声学信号特征的比较表明，气膜崩塌和汽体体积振荡是产生沸腾声的主要原因，对换热过程也有显著影响。
In this study, sound emission in subcooled pool boiling with a small plate heater was investigated experimentally. Acoustic signals were recorded using a hydrophone and analyzed using sound pressure level (SPL), fast Fourier transform, and discrete wavelet transform (DWT). The results show that the SPL combined with an analysis of the sound signal by DWT can be used to identify boiling modes and heat transfer intensification. In contrast to those for a large plate heater or long wire, the plot of the SPL against wall superheat in nucleate boiling region exhibits an ‘N” shape. Visualization results indicate that this difference mainly originates from the effects of heater size on bubble growth and departure. Compared with the nucleate boiling, in the region of microbubble emission boiling (MEB), the SPL exhibits a step increase of 10–20 dB, and continues to increase with the further increase of the heat flux. A comparison of the bubble frequency and features of the acoustic signals shows that the loud boiling sound in the MEB could be mainly attributed to the vapor film collapse and vapor volume oscillations, which also significantly affect the heat transfer process.