摘要
迎面风速和喷淋密度会影响蒸发式冷凝器的传热传质效率。本文搭建了R404A制冷系统实验台,测试了不同的迎面风速和喷淋密度下系统的冷凝压力、制冷量和能效比,并对数据进行了分析。结果表明:对于蒸发式冷凝器制冷机组,喷淋密度的控制较迎面风速更为重要;机组存在最佳迎面风速(3.1~3.3 m·s-1),在迎面风速增加到最佳值之前,风速每增加1 m·s-1,EER增加0.3~0.37,当迎面风速超过最佳值后,管外水膜将遭到破坏,蒸发式冷凝器的换热性能趋于稳定,因此冷凝压力和制冷量趋于稳定;最佳喷淋密度为0.057 kg·m-1·s-1,在喷淋密度增加到最佳值之前,喷淋密度每增加0.01 kg·m-1.s-1,EER增加0.27~0.31,当喷淋密度超过最佳值后,管外水膜变厚,水膜热阻增加,蒸发式冷凝器的换热性能减弱,因此冷凝压力升高明显,制冷量下降明显。
Air faced speed and spray density will affect the heat and mass transfer efficiency of evaporative condenser.In this paper,a R404 A refrigeration system test-bed is built,and the condensation pressure,refrigeration capacity and energy efficiency ratio of the system under different air faced speed and spray densities are tested,the data analysis is given.The results show that for evaporative condenser refrigeration units,the control of spray density is more important than the head-on wind speed,and there exists an optimal air faced speed between 3.1 m·s-1 and 3.3 m·s-1,the EER increases as 0.3 to 0.37 for every 1 m·s-1 increase of the air faced speed before the air faced speed reaches its optimum value.when the air faced speed exceeds the optimal value,the water film outside the tube will be destroyed,and the heat transfer performance of the evaporative condenser tends to be stable,consequently,the condensation pressure and refrigeration capacity tend to be stable.The optimum spray density is 0.057 kg·m-1·s-1,before the spray density increased to the optimum value,the EER increased by 0.27 to 0.31 with the spray density increasing by 0.01 kg·m-1·s-1.when the spray density exceeds the optimum,the water film outside the tube becomes thicker,and the thermal resistance of water film increases,and the heat transfer performance of the evaporative condenser is reduced,consequently,the condensation pressure increases obviously and the refrigeration capacity decreases obviously.
作者
杨永安
宣朝辉
王飞飞
YANG Yong-An;XUAN Chao-Hui;WANG Fei-Fei(Tianjin Key Laboratory of Refrigeration Technology,Tianjin University of Commerce,Tianjin 300134,China)
出处
《工程热物理学报》
EI
CAS
CSCD
北大核心
2020年第7期1751-1756,共6页
Journal of Engineering Thermophysics
基金
天津市应用基础与前沿技术研究计划(No.16JCQNJC06600)。
