磁致伸缩换能器驱动的热声制冷机微型化基础问题研究

发布时间：2018-10-15 11:14

【摘要】：热声制冷是一种全新的制冷技术，它基于热声效应的原理，具有结构简单、运行稳定、寿命较长、低噪声等优点。尤其是微型热声制冷机在微电子散热冷却方面具有不可比拟的优势。本文首先讲述了微型热声制冷机的研究背景及其意义，对其国内外的发展过程进行了较为详细的论述。对从发现热声效应现象以来提出的种种理论进行了汇总说明。从热力学角度对声制冷的过程进行了详细的定性分析。也对热声效应所触及到的流体力学、传热学等基本知识进行了说明。从而对微型热声制冷机有一个较为完整的认知。为了验证采用Fluent对热声声场进行数值模拟的可行性，首先对直管进行了流场的模拟，模拟结果与理论的结果波形分布趋同，从而说明了采用Fluent软件进行数值模拟的可行性。本文设计了一种加强型的微型热声制冷机，通过对谐振管的前端引入了一段锥形管和通过调节尾腔纵向尺寸达到共振，两者共同作用提高了谐振管的振幅幅度，进而提高了热声制冷机的制冷效率。为了具体的研究一块板叠的制冷特性，本文现在谐振管内放置了一块板叠，并对板叠在下不同动压条件下的制冷特性进行了模拟对比。并在板叠的左右两端分别取两个点作为监测点，直观的表现出了板叠两端两点的制冷和制热的温度具体变化过程。谐振管内形成了一定的温度梯度，同时也验证了声致冷效应。引入了完整的回热器和换热器，对整个热声制冷机进行了数值模拟分析，其中的换热器采用多孔流体域来进行数值模拟分析。观测到了回热器中与换热器过度区域出现的非线性现象。重点对其板叠不同流道内的温度、压力、速度的变化情况进行了探究。选取流道内一点进行监测，并观测其温度、压力、速度随时间的变化规律。也对某一时刻整个制冷机中轴线上的温度进行了分析。最后通过对比不同的压力和频率对回热器内流体状态的影响，，得出了选取合适的压力和频率对热声制冷机制冷效率的提升具有重要作用的结论。最后对本论文进行了总结，并且列举了几点研究成果，创新性的设计了加强型的微型热声制冷机，并对制冷机的特性进行了数值模拟分析。也指出了论文的不足之处。
[Abstract]:Thermoacoustic refrigeration is a new refrigeration technology, which is based on the principle of thermoacoustic effect. It has the advantages of simple structure, stable operation, long life, low noise and so on. Especially the micro thermoacoustic refrigerator has an incomparable advantage in microelectronic cooling. In this paper, the research background and significance of micro thermoacoustic refrigerator are introduced, and the development process of micro thermoacoustic refrigerator at home and abroad is discussed in detail. The theories put forward since the discovery of thermoacoustic effect are summarized and explained. The process of acoustic refrigeration is analyzed qualitatively in detail from the point of view of thermodynamics. The basic knowledge of fluid mechanics, heat transfer and so on, which is touched by thermoacoustic effect, is also explained. Thus the miniature thermoacoustic refrigerator has a relatively complete understanding. In order to verify the feasibility of numerical simulation of thermoacoustic field by using Fluent, the flow field of the straight pipe is first simulated. The simulation results are similar to that of the theoretical results, which shows the feasibility of numerical simulation using Fluent software. In this paper, an enhanced miniature thermoacoustic refrigerator is designed. By introducing a section of tapered tube to the front end of the resonant tube and reaching resonance by adjusting the longitudinal size of the tail cavity, the amplitude of the resonant tube is increased by the combined action of the two. Furthermore, the refrigeration efficiency of thermoacoustic refrigerator is improved. In order to study the refrigeration characteristics of a plate stack, a plate stack is placed in the resonant tube in this paper, and the refrigeration characteristics of the plate stack under different dynamic pressure are simulated and compared. Two points are taken as the monitoring points at the left and right ends of the plate stack respectively. The temperature variation process of the two points of the plate stack is shown intuitively. A certain temperature gradient is formed in the resonant tube, and the acoustic cooling effect is also verified. The whole thermoacoustic refrigerator is numerically simulated by introducing a complete regenerator and heat exchanger. The heat exchanger is numerically simulated in porous fluid domain. The nonlinear phenomena in the transition region between the regenerator and the heat exchanger are observed. The variation of temperature, pressure and velocity in different channels of the laminate is discussed. A point in the channel is selected to monitor and observe the variation of temperature, pressure and velocity with time. The temperature on the axis of the whole refrigerator at a certain time is also analyzed. Finally, by comparing the influence of different pressure and frequency on the fluid state in the regenerator, it is concluded that the proper pressure and frequency play an important role in improving the refrigeration efficiency of the thermoacoustic refrigerator. Finally, this thesis is summarized, and several research results are listed. The enhanced miniature thermoacoustic refrigerator is designed innovatively, and the characteristics of the refrigerator are analyzed numerically. Also pointed out the shortcomings of the paper.
【学位授予单位】：内蒙古科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TB657

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