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在工况温度分别为6℃和10℃,对R134a在光管和三根双侧强化管(F38,F46,F56)外进行池沸腾换热试验研究。结果表明:两种工况下,R134a在光管外沸腾表面传热系数与Cooper公式计算值相对偏差均在±15%以内,R134a在强化管外沸腾表面传热系数变化趋势与光管Cooper公式基本一致。受试验管外表面孔隙直径的影响,当热流密度小于50k W/m2(或壁面温差小于2K)时,孔隙直径越小,沸腾换热效果越好;反之,当热流密度大于50k W/m2(或壁面温差大于2K)时,孔隙直径大的强化表面沸腾换热效果要优于小孔隙直径表面。
Under the conditions of working temperature of 6 ℃ and 10 ℃ respectively, the pool boiling heat transfer test of R134a was carried out in the light pipe and three double-sided reinforced pipes (F38, F46, F56). The results show that the relative deviation between R134a and Cooper formula is within ± 15% under both conditions, and the trend of the R134a heat transfer coefficient outside the tube surface is similar to that of Cooper equation Basically the same. When the heat flux is less than 50k W / m2 (or the wall temperature difference is less than 2K), the smaller the pore diameter is, the better the boiling heat transfer is. When the heat flux is more than 50k W / m2 Or the wall temperature difference is greater than 2K), the enhanced surface boiling heat transfer effect with larger pore diameter is better than the small pore diameter surface.