| 摘要: |
| 通过实验研究了室外换热器采用平直、波纹、波纹/开缝翅片对热泵空调器动态结霜性能的影响。结果表明，在结霜工况下，平直、波纹、波纹/开缝三种翅片类型的系统制热量、COP和压缩机功率的峰值、平均值依次增大，其中，波纹/开缝翅片的各项平均值比平直翅片分别减小了14.57%、8.26%和7.11%。波纹/开缝翅片的性能参数最早开始衰减且衰减幅度也最大，其次是波纹翅片，平直翅片最晚开始衰减且幅度最小。结霜时，水蒸气变为霜的相变过程对传热具有强化作用，同时霜层减小了翅片间隙使风阻增大、室外风机流量减小，这对传热具有恶化作用。结霜时性能参数的曲线存在上升段和衰减段，与霜层微观成长特性一致：结霜初期，冰晶由粒状变为柱状，尚未显著阻塞翅片间隙，对传热的强化作用较显著，曲线处于上升段；结霜中后期，冰晶先沿半径成长，后又在柱状晶间隙堆垛，对传热的恶化作用较显著，曲线处于衰减段。 |
| 关键词: 热工学 翅片类型 热泵空调 COP 结霜 |
| DOI： |
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| 基金项目: |
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| Effect of Fin Type on Frosting Characteristics of an Air-source Heat Pump |
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Huang Dong, Liu Xiaoyu, Wang Yanlu
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| (School of Energy and Power Engineering, Xi'an Jiaotong University) |
| Abstract: |
| The effects of fin type of outdoor coil in an air-source heat pump unit on the dynamic frosting characteristics were experimentally investigated. The fins include the flat, wavy and wavy/slit type. The decreasing orders of both the average and maximum values of the heating capacity, COP and input power are flat, wavy and wavy/slit fins under the frosting condition. The average values of heating capacity, COP and input power for the wavy/slit fin are decreased by 14.57%, 8.26% and 7.11% respectively than those for the flat fin. The performance parameters for the wavy/slit fin decrease earliest and most greatly, then for the wavy fin, and finally for the flat fin. The frost has the advantage of enhancing the air-side heat transfer coefficient due to the phase change from vapor to frost. Meanwhile, it has the disadvantage of decreasing the fan airflow rate across the outdoor coil because the frost decreases the fin spacing and increases the air pressure drop. The curves of the performance parameters have the ascending and descending segments during the frosting period, which accords with the microcosmic growth characteristics of the frost. In the early stage of frosting cycle, the frost crystal grows from the grain shape to the column one which does not decrease the fin spacing remarkably, so the advantage of the frosting is greater than its disadvantage, which results in the ascending segment of performance. In the middle and final stages, the frost crystal grows along the radius direction, then stacks up between the frost columns, so the fin spacing is decreased remarkably and the disadvantage of the frosting is greater than its advantage. |
| Key words: Pyrology Fin type Heat pump COP Frosting |
