【摘要】 为了探究真空下水平管内流动冷凝的传热状况,以水为工质,在3个不同冷凝温度(45、55和65℃),质量流速为5~12 kg/(m~2·s)和蒸汽干度为0~0.9的范围内,对水平管内流动冷凝的传热特性进行了试验研究。着重探讨了质量流速、干度和冷凝温度等参数对管内传热系数的影响,并详细分析了水平管内流动冷凝的传热机理。试验结果表明:管内传热系数随蒸汽干度的减小而降低,且变化幅度较大;蒸汽质量流速和冷凝温度对管内传热系数在低干度区内影响较小,而在高干度区内影响较大。更多还原

【Abstract】 To study the heat transfer state of flow condensation in the horizontal tube in vacuum mode, the water was taken as the working medium, the heat transfer characteristics of flow condensation in a horizontal tube was tested and studied at three condensation temperature(45, 55 and 65 ℃), mass flow of 5 ~ 12 kg/(m~2·s) and the vapor quality of 0 ~ 0.9. In addition, the influence of the mass flow, the vapor dryness quality and the condensation temperature on the heat transfer coefficient inside the tube was disscussed, and the heat transfer mechanism of flow condensation in the horizontal tube was analyzed in detail. The test results showed: the heat transfer coefficient inside the tube decreased with the increase in the vapor dryness fraction, and the variation amplitude was large; the mass flow of the vapor and the condensation temperature had slight impact on the heat transfer coefficient inside the tube at low vapor quality, while had remarkable impact at high vapor quality.更多还原