超低温冷链用小型热声制冷机研究

 2022-04-07 08:04

论文总字数:34119字

摘 要

部分生鲜食品、疫苗、医学标本等的运输及储存需要超低温冷链来提供保障,通常温度在-60~-100℃左右。现有的超低温冷链多采用传统蒸汽压缩式制冷技术,所用的工质以氟利昂为主,对生态环境有较大的影响。再者,蒸汽压缩式制冷技术一方面因结构复杂、维护多,很难满足小型化、移动化等应用场合的需求;另一方面,随着温度的降低,其单位制冷量的能耗快速上升,制冷性能也随之降低。寻找环保、可靠、可移动化、高效的制冷技术受到了越来越多科研人员的关注。

热声制冷技术是一种新型的制冷技术,它基于热声原理实现制冷效应,具有环保、可靠性好、结构紧凑、效率高等优点。本文研制了一台小型电驱动热声制冷机。首先利用DeltaEC软件进行了热力学设计,综合考虑并分析运行参数与结构参数对制冷机性能的影响。根据计算结果,在工作压力为6.55MPa、频率为94Hz,输入声功为350W时,制冷机在173K制冷温度下可获得227.5W的设计制冷量,整机相对卡诺效率达到30%以上。其次,根据优化设计的结果,利用Solidworks软件完成了结构设计,并对零部件进行了加工,装配了实验样机并搭建了实验台进行初步实验。最后,对实验结果进行了分析,为制冷机的进一步优化提供依据。

关键词:超低温冷链,热声制冷机,电驱动,DeltaEC

Abstract

The transportation and storage of some fresh foods, vaccines, medical specimens, etc. require ultra-low temperature cold chain to provide protection, and the temperature is around -60~-100 °C. The existing ultra-low temperature cold chain mostly adopts the traditional vapor-compression refrigeration technology. The working medium is mainly Freon, which has a great influence on the ecological environment. Furthermore, the vapor-compression refrigeration technology is difficult to meet the needs of miniaturization and mobilization due to its complicated structure and maintenance. In addition, as the temperature decreases, the energy consumption per unit of cooling capacity rises rapidly, and the performance of refrigeration also decreases. Finding environmentally friendly, reliable, mobile, and efficient refrigeration technologies has attracted the attention of more and more researchers.

Thermoacoustic refrigeration technology is a new type of refrigeration technology. It realizes the cooling effect based on the thermoacoustic principle. It has the advantages of environmental friendliness, reliability, structure compactness and efficiency. This paper developed a small electric-driven thermoacoustic refrigerator. Firstly, the thermodynamic design was carried out by using DeltaEC software. The effects of operating parameters and structural parameters on the performance of the refrigerator were comprehensively considered and analyzed. According to the calculation results, when the working pressure is 6.55 MPa, the frequency is 94 Hz, and the input sound power is 350 W, the cooler can obtain 227.5 W design cooling capacity at 173 K cooling temperature, and the relative Carnot efficiency of the machine reaches 30%. Secondly, according to the results of optimization design, Solidworks software was used to carry out structural design as well as parts processing. The prototype refrigerator was developed and tested. Finally, the experimental results are analyzed to provide some clues for further optimization of the refrigerator.

KEY WORDS: ultra-low temperature cold chain, thermoacoustic refrigerator, electric-driven, DeltaEC

目 录

摘 要 I

Abstract II

第一章 绪论 1

1.1 课题研究背景 1

1.2 热声研究进展 1

1.2.1 热声效应的发现 1

1.2.2 热声理论的发展 1

1.3 电驱动热声制冷机研究进展 2

1.3.1 热声制冷机简介 3

1.3.2 研究进展 3

1.4 本文研究目的和主要研究内容 7

第二章 热声制冷机热力学设计 9

2.1 热声制冷机计算模型 9

2.1.1. DeltaEC计算模型简介 9

2.1.2. 直线压缩机理论模型 11

2.1.3. 制冷机计算模型 13

2.2 设计参数的影响 15

2.2.1 制冷机性能评价 15

2.2.2 结构参数对制冷机性能影响 18

2.2.3 运行参数对制冷机性能影响 35

2.3 直线压缩机参数选择 40

2.4 优化设计结果 41

第三章 热声制冷机的结构设计 43

3.1 结构模型设计 43

3.1.1 室温端换热器 43

3.1.2 回热器 44

3.1.3 冷端换热器与端盖 45

3.1.4 电机外壳 46

3.1.5 整机配合 47

3.2 测量系统 48

3.2.1 压力的测量 49

3.2.2 制冷量的测量 50

3.2.3 温度的测量 50

3.3 实验步骤 50

3.4 实验结果及分析 50

3.4.1 无负荷制冷温度 50

3.4.2 制冷量 51

3.4.3 实验数据分析 52

结 论 54

参考文献 55

致 谢 57

  1. 绪论
    1. 课题研究背景

随着经济发展、生活水平不断提高,人们的消费观念逐渐开始转变,对生鲜食品品质的要求也逐渐提升。如何保证输运途中生鲜食品的营养和新鲜程度,已经引起了社会的广泛关注。例如金枪鱼鱼肉需要在-60℃的低温环境下保存,才能保证营养和品质,若在物流中温度变化次数多,金枪鱼的品质会大大下降[1]。事实上,其它鱼类肉类也随着温度的降低,保存时间延长、品质维持更好。此外,近年来随着生物医学工程的发展,用于科研、医疗的深冷冰箱也愈发重要,对便携性的要求也越来越高。-86℃系列的深冷冰箱用于药品与医学标本的储存,更有低于-100℃的深冷低温冰柜用于特殊材料的超低温实验。

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