| 摘要: |
| 在重力供液系统中，供液压头大于蒸发器对冷媒的阻力，液体冷媒就可以在蒸发器与汽液分离器的回路中再循?环，再循环作用的强弱用循环倍率表示。循环倍率与供液压头和蒸发温度有关。这里推导了运用均相流模型计算蒸发回路各种阻力的计算公式，针对一小型制冷系统和专门设计的再循环蒸发器，进行阻力平衡计算。在此基础上，用空气侧热平衡法对该制冷系统进行了供液压头与蒸发温度和循环倍率的相互影响实验。结果表明：所推导的阻力计算式具有工程应用精度；蒸发温度升高循环倍率减小，且蒸发温度较低时循环倍率的变化率较小，反之亦然；供液压头增大循环倍率增大，而单位供液压头引起的循环倍率变化却随压头的增大而减小，该变化率还随蒸发温度的升高不断缩小；循环倍率有最优值，推荐的循环倍率应在4~5之间。 |
| 关键词: 热工学 再循环蒸发器 重力供液蒸发器 均相流模型 循环倍率 |
| DOI： |
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| 基金项目: |
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| Effect of the Supply Liquid Pressure Hydraulic Head and Evaporation Temperature on the Circulating Rate of Circulating Evaporator |
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Dai Yajing, Zang Runqing, LiXing
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| (Department of Refrigeration &Air Conditioning Engineering, Tianjin University of Commerce,Tianjin Key Laboratory of Refrigeration Technology) |
| Abstract: |
| For gravity feeding refrigeration system, when the hydraulic head was greater than the resistance to the evaporator, liquid refrigerant can recycle in loop formed by the evaporator and vapor-liquid separator. The strength of recycling was expressed by circulating rate, which was connected with hydraulic head and evaporation temperature. Resistance formulas to a small system were derived and a special recycling evaporator was designed. Resistance balance calculation in homogeneous flow model was completed. Then the effect of hydraulic head and evaporation temperature on the circulating rate of refrigeration system was experimentally investigated using the air-side heat balance method. The results showed the precision can be satisfied with the engineering demand. Cycling rate decreases as evaporation temperature increases, and the lower the evaporation temperature is, the smaller the change of cycling rate. Cycling rate increases as hydraulic head increases, and the augment formed by one unit hydraulic head increases with the decrease of hydraulic head. The changing rate decreases with the increase of evaporation temperature and there exists optimal cycling rate which is recommended as 4~5. |
| Key words: Pyrology Recycling evaporator Gravity feeding refrigeration evaporator Homogeneous flow model Circulating rate |
