翅片管降膜冷凝器的实验研究

发布时间：2018-01-07 23:00

本文关键词：翅片管降膜冷凝器的实验研究　出处：《华南理工大学》2016年硕士论文　论文类型：学位论文

【摘要】：为探索在保证空调器性能的同时,减少制冷剂充注量的解决方案,本文设计了用于翅片管降膜冷凝器,并将其改装于某品牌家用空调器上进行实验研究,并在标准焓差室中进行四个制冷工况下的换热性能及充灌量对比实验。使用了降膜冷凝器的改良机有三组充灌量,分别为:550g、650g、750g,而用于对比参照测试的标准机充灌量为出厂标配的1050g。本文在目前通用的空调风冷冷凝器的结构、制冷剂物性数据的基础上,建立了换热性能计算模型和制冷剂积存量计算模型,分析制冷工况和充灌量对冷凝器换热系数和制冷剂积存量的影响。根据换热性能计算模型所得到的分析数据显示:换热系数随质量流率的增加而提高,改良机在充灌量为650g和750g时,过热段管内换热系数平均要比标准机冷凝器高8.8%和10.7%,在两相段平均要高7.8%和16%,冷凝器整体传热系数的提升达到29.6%~45.3%。根据制冷剂积存量计算模型所得到的分析数据显示:降膜冷凝器中液膜厚度的最大值为0.066mm,远小于标准机冷凝器两相段的液膜厚度,并且液膜厚度减薄在提高换热系数的同时也减少了制冷剂积存量,在四个不同制冷工况下,标准机冷凝器中制冷剂积存量占充灌量的54%~65%,,而改良机在减少充灌量的情况下,降膜冷凝器中的制冷剂积存量仅占充灌量的17%~34%。根据对冷凝器翅片表面的热像图的分析得知:降膜冷凝器的两相段制冷剂侧换热温差要比标准机更小,并且当充灌量达到650g以上时,降膜冷凝器翅片表面平均温度要大于标准冷凝器,即在相同的工作环境下有着更大的管外换热温差,保证了换热量能够维持在较高的水平上。
[Abstract]:In order to explore the solution of reducing refrigerant charge while ensuring the performance of air conditioner, this paper designed a finned tube falling film condenser and modified it to a brand of domestic air conditioner for experimental study. In the standard enthalpy difference chamber, the heat transfer performance and the filling rate were compared under four refrigerating conditions. The improved machine with falling film condenser has three groups of filling capacity, which are respectively: 550g / kg 650g / 750g / g. The standard machine charge and filling quantity used for comparison and test is 1050g. this paper is based on the data of the structure and refrigerant physical properties of the air-cooled condenser in general air conditioning at present. The calculation model of heat transfer performance and refrigerant accumulation is established. The influence of refrigeration condition and charge rate on the heat transfer coefficient and refrigerant accumulation of condenser is analyzed. According to the analysis data obtained from the model of heat transfer performance, the heat transfer coefficient increases with the increase of mass flow rate. When the filling capacity of the improved machine is 650g and 750g, the average heat transfer coefficient in the overheating section is 8.8% and 10.7g higher than that in the standard condenser, and 7.8% and 16% higher on the average in the two-phase section. The overall heat transfer coefficient of the condenser has reached 29.6 and 45.3.The analytical data obtained from the refrigerant accumulation calculation model show that:. The maximum thickness of liquid film in the falling film condenser is 0.066 mm. The thickness of liquid film is much smaller than that of the two-phase condenser of standard machine, and the thinning of liquid film thickness not only increases the heat transfer coefficient, but also reduces the refrigerant accumulation under four different refrigeration conditions. The refrigerant accumulation in the standard machine condenser accounts for 54% of the charge, while the improved machine is reducing the charge. The amount of refrigerant accumulated in the falling film condenser is only 17% of the filling capacity. According to the analysis of the thermogram of the fin surface of the condenser, it is known that:. The temperature difference of the two phase refrigerant side of the falling film condenser is smaller than that of the standard machine. The average surface temperature of the fin of the falling film condenser is higher than that of the standard condenser when the filling quantity is more than 650 g, that is, there is a larger difference of heat transfer temperature outside the tube under the same working environment. It ensures that the heat transfer can be maintained at a higher level.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TB657.2

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