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首页> 外文期刊>Journal of Heat Transfer >Water-Heated Pool Boiling of Different Refrigerants on the Outside Surface of a Horizontal Smooth Tube
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Water-Heated Pool Boiling of Different Refrigerants on the Outside Surface of a Horizontal Smooth Tube

机译：水平光滑管外表面上不同制冷剂的水加热池沸腾

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Pool boiling heat transfer has been extensively studied over decades, but the effect of boundary heating conditions on boiling received little attention. In this work, heat transfer coefficients during pool boiling of five different refrigerants (R123, R245fa, R236fa, R134a, and R22) on the outside surface of a smooth copper lube were measured at the saturation temperature of 6.7 ℃; water flows inside the tube and provides heat to the refrigerants to boil (thus, water-heated boiling). Measurements showed that the refrigerant of a higher vapor pressure has a higher heat transfer coefficient, with the exception that R22 performs nearly the same as R134a. A correlation previously developed for electrically-heated pool boiling on cylindrical tubes underpredicts by 30%-46% the heat transfer coefficients during water-heated boiling of the five refrigerants. Among the pool boiling correlations reviewed in this work, the Cooper correlation (for pool boiling on cylindrical tubes) predicts the boiling heat transfer coefficients of R22 and R245fa reasonably well (within ±8.5%), but not as well those of the other three refrigerants (underpredicts by nearly 30% for R134a and R236fa and overpredicts by nearly 40% for R123). It is found that the predicted boiling heat transfer coefficients of the Jive refrigerants by the modified Gorenflo correlation (simply adding a constant multiplier of 1.47 to the Gor-enflo correlation) are in excellent agreement with their respective measurements.
机译：数十年来对池沸腾传热进行了广泛的研究，但是边界加热条件对沸腾的影响却很少受到关注。在这项工作中，在6.7℃的饱和温度下，测量了光滑铜润滑油外表面上的五种不同制冷剂（R123，R245fa，R236fa，R134a和R22）在池沸腾过程中的传热系数；水在管内流动，并向制冷剂提供热量使其沸腾（因此，水加热沸腾）。测量表明，蒸气压较高的制冷剂具有较高的传热系数，不同之处在于R22的性能几乎与R134a相同。以前为圆柱管上的电加热池沸腾建立的相关性将五种制冷剂的水热沸腾过程中的传热系数低估了30％-46％。在这项工作中回顾的池沸腾相关性中，库珀相关性（对于圆柱管上的池沸腾）预测R22和R245fa的沸腾传热系数相当好（在±8.5％之内），但其他三种制冷剂的沸腾传热系数却不那么好（R134a和R236fa的预测值将近30％，R123的预测值将近40％）。可以发现，通过改进的Gorenflo相关性（简单地将Gor-enflo相关性增加1.47的常数倍数），Jive制冷剂的预测沸腾传热系数与它们各自的测量结果非常吻合。

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