自动复叠式制冷系统的循环特性及实验研究

发布时间：2018-11-22 09:54

【摘要】：随着航空航天工业，金属制品、电子元件，和冶金产品等特殊行业对深冷低温的需求，自动复叠式制冷因其结构简单、系统稳定性能好，同时可以满足在普冷领域的低温环境要求，而逐渐受到广泛的重视。鉴于此，本文采用单级压缩、一级分凝的形式，选用非共沸工质对R22/R23为混合制冷剂，基于热力学第一定律和热力学第二定律对系统进行热力循环特性分析，随后实验研究了不同配比、不同蒸发温度和不同分液比等系统参数对系统性能的影响。主要得出了以下结论： 1）基于热力学第一定律和热力学第二定律，结合自动复叠式制冷的热力学模型，研究了R22分液比、R22/R23工质对配对、压比、蒸发温度和加热量对系统性能的影响。结果表明：当R22进入蒸发冷凝器的份额越大时，随着R22与R23的质量流量比的增大，系统的COP也相应的增加；R22与R23的配比在1.0~1.8范围内，，与COPL成正相关。 2）搭建了R22/R23自动复叠式制冷系统实验平台，实验研究了不同配比和R22分液比对系统性能的影响。结果表明：在系统开始运行后的5分钟内，低温箱内的温度和低温蒸发器的进出口温度骤减；在不同的配比下，系统都能够在30分钟内达到稳定运行的状态；在不同的蒸发温度下，当工质对分液比比在0.6~0.65范围内，系统都存在一个总COP的极值。本文的创新在于选择设计的自动复叠式制冷系统有两个蒸发箱，高温箱和低温箱同时制冷，产生制冷量，不仅可以研究常规的蒸发冷凝器和低温箱的换热和制冷特性，还充分的利用了工质间的复叠，使高沸点工质的余热得到了充分的利用，改善了系统的性能。本文关于双温蒸发箱的实验性能研究对于一机多温的冷库和冰箱等制冷领域具有十分重要的指导与参考价值。
[Abstract]:With the special demand for cryogenic and low temperature in aerospace industry, metal products, electronic components and metallurgical products, automatic cascade refrigeration has the advantages of simple structure and good system stability. At the same time, it can meet the requirements of low temperature environment in the field of general cooling, and has been paid more and more attention. In view of this, this paper adopts the form of single-stage compression and first-order condensation, selects non-azeotropic working fluid pair R22/R23 as the mixed refrigerant, and analyzes the thermodynamic cycle characteristics of the system based on the first law of thermodynamics and the second law of thermodynamics. Then, the effects of system parameters such as different ratio, different evaporation temperature and different ratio of liquid to liquid on the system performance were studied. The main conclusions are as follows: 1) based on the first law of thermodynamics and the second law of thermodynamics, combined with the thermodynamic model of auto-cascade refrigeration, the R22 component liquid ratio, R22/R23 working pairs and pressure ratio are studied. The effect of evaporation temperature and heat addition on system performance. The results show that when R22 enters the evaporative condenser, the COP of the system increases with the increase of mass flow ratio of R22 to R23, and the ratio of R22 to R23 is in the range of 1.0 ~ 1.8, which is positively correlated with COPL. 2) the experimental platform of R22/R23 automatic cascade refrigeration system is built, and the effects of different ratio of R22 and R22 on the performance of the system are studied experimentally. The results show that the temperature in the cryogenic box and the inlet and outlet temperature of the cryogenic evaporator decrease sharply within 5 minutes after the system starts running, and the system can reach a stable operation state in 30 minutes under different ratios. At different evaporation temperatures, there is a total COP extremum in the system when the ratio of working medium to liquid is in the range of 0.6 ~ 0.65. The innovation of this paper is that the automatic cascade refrigeration system designed in this paper has two evaporators, the high temperature box and the low temperature box to refrigerate at the same time to produce the refrigerating capacity, which can not only study the heat transfer and refrigeration characteristics of the conventional evaporative condenser and the low temperature box. It also makes full use of the overlay between the working fluids, which makes full use of the waste heat of the high boiling point working fluid, and improves the performance of the system. In this paper, the experimental performance of the double-temperature evaporator is very important for the refrigeration field such as a multi-temperature refrigerator and a refrigerator.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TB657

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