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以有机朗肯循环系统(ORCs)蒸发器中的蒸发段管内相变传热和流动为对象,基于热力学第一和第二定律,分别对回收和损失,提出了能否忽略工质流动损失的判据,即无因次变数NΔE。分别以外翅片管和光管为例,分析了翅片管结构参数ηoβ、管内雷诺数Rei和蒸发温度Tv对NΔE的影响。结果表明:对于回收,当其他条件不变时,随着Rei的增加,NΔE,r逐渐减小,当NΔE,r小于10时,不可忽略流动损失;当NΔE,r=10时的外翅片管Rei的临界值比光管的大;对于损失,当其他条件不变时,任何管型的NΔE,l值均远大于10,可忽略工质流动引起的损失。
Based on the first law and the second law of thermodynamics, the heat transfer and the flow in the evaporating section of organic Rankine cycle (ORC) evaporator were studied respectively. The criterion of loss, that is, dimensionless variable NΔE. Taking the finned tube and the optical tube as examples, the influence of the structural parameters ηoβ, Reynolds number Rei and evaporating temperature Tv on the NΔE were analyzed. The results show that for the recovery, NΔE, r decreases with the increase of Rei when other conditions remain unchanged. When NΔE, r is less than 10, the flow loss can not be neglected. When NΔE, r = 10 The critical value of fin tube Rei is larger than that of a light pipe. For other losses, the values of NΔE and L for any tube are much larger than 10, neglecting the loss due to the flow of working fluid.