多孔表面沸腾临界热流密度提升的实验研究

Experimental study on the increase of boiling critical heat flux on porous surface

传热表面形成的多孔层,由于增加成核点的数量和增强液体供应能力,可以显著提升沸腾换热性能。在此研究中,应用电化学沉积法制备多孔表面且其表面特性被呈现。多孔表面的沸腾传热性能在常压饱和池沸腾条件下被测试。沉积时间和有无低电流沉积过程对沸腾特性的影响被研究。实验结果表明:与普通表面相比,多孔表面显著提高了沸腾传热性能。随着沉积时间的增加,沸腾传热临界热流密度(q_(c))呈上升趋势;增加低电流沉积过程可实现q_(c)显著提升。在此研究的实验条件下,沸腾传热q_(c)和传热系数h的提升比例分别为41%—145%和37%—156%。多孔表面沸腾传热性能的提升机理归因于其毛细芯吸力的提升。

A porous layer formed on the heated surface can enhance boiling heat transfer performance due to the increased number of nucleation sites and the enhanced ability of liquid supply.In the present study,porous layers were developed by the electrodeposition method and the responsible surface morphology was reported.The boiling heat transfer performance with a porous layer was investigated experimentally in saturated pool boiling of water under the atmospheric pressure condition.The effects of deposition time and low current deposition process on boiling characteristics were studied.The experimental results show that compared with the plain surface,the porous surface significantly enhances the boiling heat transfer performance.The critical heat flux(q_(c))of boiling heat transfer show an increment trend with the increasing deposition time and adding low current deposition process.In the experimental conditions,the enhancement ratio of the q_(c) and the heat transfer coefficient h are 41%-145%,and 37%-156%,respectively.The q_(c) enhancement mechanism for the porous layer is attributed to its improvement in capillary wicking.