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本文对含Solest-120冷冻油的R134a,在饱和温度为5℃和10℃工况下,在水平高效强化管(管E21.为C3型管,管E22为A1型管)管外池沸腾换热进行了实验研究。实验结果表明:与相同管径的光管的换热性能相比,强化管E21、E22的管内传热系数强化倍率分别为3.703和3.035。随着含油浓度的增加,管外池沸腾换热效果得到优化,含油率为1.0×10~(-4)时的管外传热系数比含油5.0×10~(-5)时更高,在实验研究的水流速范围内,在蒸发温度为5℃时增加了3.7%～7.2%,而在蒸发温度为10℃时增加了0.8%～10.9%。从含油R134a的黏度、表面张力等的角度,对含油率高时换热系数大的结论进行了必要的物理解释。研究对开发设计蒸发器有一定实际的指导意义。
In this paper, R134a containing Solest-120 frozen oil was heated in boiling water at a temperature of 5 ℃ and a temperature of 10 ℃. An experimental study was carried out. The experimental results show that compared with the heat transfer performance of the same diameter light pipe, the enhancement magnification of heat transfer coefficient in the pipe of E21 and E22 are 3.703 and 3.035, respectively. With the increase of oil concentration, the effect of boiling heat transfer outside the tube is optimized. The heat transfer coefficient outside the tube is higher when the oil content is 1.0 × 10 ~ (-4) than when the oil content is 5.0 × 10 ~ (-5) The range of water velocities studied increased by 3.7% -7.2% at an evaporation temperature of 5 ° C and by 0.8% -10.9% at an evaporation temperature of 10 ° C. From the perspective of viscosity and surface tension of oil-containing R134a, the necessary physical explanation is given for the conclusion that the heat transfer coefficient is high when the oil content is high. Research on the development and design of the evaporator has some practical significance.