过冷度和粗糙度对铁铬铝平板淬冷沸腾影响的实验研究

Experimental Study on Effect of Subcooling Degree and Roughness on Quenching Boiling of FeCrAl Plate

为了探究过冷度和表面粗糙度对铁铬铝(FeCrAl)平板淬冷沸腾的影响,对FeCrAl平板在不同过冷度和表面粗糙度下的淬冷沸腾过程开展了可视化实验研究。采用热电偶测量平板内部温度,并利用导热反问题解析式求解平板表面温度和热流密度;通过对比分析实验现象,探究过冷度和表面粗糙度对平板淬冷沸腾过程的影响,并建立了过冷度与最小膜态沸腾温度的关系式。结果表明,淬冷沸腾过程中,FeCrAl平板表面形成开尔文一亥姆霍兹(K-H)不稳定波,且气膜破裂后产生的骤冷前沿呈“抛物线”状;随着过冷度的增加,最小膜态沸腾温度增大,临界热流密度增大,平板表面冷却速率加快,淬冷沸腾过程的时长缩短;较大的表面粗糙度可以促进FeCrAl平板表面淬冷沸腾的进行,但影响微小。

In order to investigate the effect of subcooling degree and surface roughness on the quenching boiling process of FeCrAl plate,a visual experimental study is carried out on the quenching boiling process of FeCrAl plate under different subcooling degree and surface roughness.The temperature inside the plate is measured by thermocouple,and the surface temperature and heat flux of the plate are solved analytically by using the inverse problem of heat conduction;Through the comparative analysis of the experimental phenomena,the effect of subcooling degree and surface roughness on the plate quenching boiling process is investigated,and the relationship between subcooling degree and the minimum film boiling temperature is established.The results show that during the quenching boiling process,the Kelvin-Helmholtz unstable wave is formed on the surface of the plate,and the sudden cooling front caused by the rupture of the gas film is in the shape of“parabola”.With the increase of subcooling degree,the minimum film boiling temperature and critical heat flux increase,the cooling rate of plate surface increases,and the duration of quenching boiling process shortens;Larger surface roughness can promote the progress of quench boiling on flat surfaces but the effect is small.