风冷热泵蒸发器结霜性能的研究

建立了一个可以反映风冷热泵翅片管式蒸发器局部特性的数学模型,该模型考虑了蒸发器在干、湿、霜工况下传热、传质的差异以及霜层沿管子变化的情况。对常用的翅片管式蒸发器进行了理论研究,计算结果表明:蒸发器表面霜层分布极不均匀,影响了换热。同时提出了新型改进蒸发器结构,结果表明改进效果良好,普通换热器换热性能下降的速度是改进型换热器的1.5倍。数值计算的结果和实验测试的结果吻合良好,证明了数学模型的正确性与可靠性。

Study on Frosting of Air- Cooled Heat Pump Evaporator

A mathematical model of air-cooled heat pump finned-tube evaporator was been set up to calculate local performance of the evaporator.The model considers the difference of heat and mass transfer under dry,wet,and frosting conditions and the frost formation varying along tubes.The ordinary finned-tube evaporator was studied theoretically.The computing result shows that the frost layer is not very uniform on the evaporator and it reduces heat transfer of the evaporator.An improved evaporator structure was developed and the heat transfer falling rate of the ordinary evaporator is1.5times larger than that of the improved one.The numerical results are in good agreement with the experimental data.