径流型深度膨胀式气波制冷机性能研究

发布时间：2018-02-15 21:24

本文关键词： 气波制冷制冷效率制冷温降振荡管激波　出处：《大连理工大学》2014年硕士论文　论文类型：学位论文

【摘要】：气波制冷机是一种利用气体膨胀进行制冷的新型制冷设备,本文以径向过膨胀气波制冷机为研究对象,运用数值模拟的方法并结合气体动力学理论对其内部流场以及制冷流程进行了较为深入的研究。研究成果对气波制冷机效率的提高和制冷流程的优化具有一定的参考价值。主要研究内容如下： (1)利用激波理论解释了气波制冷机的工作机理,推导了激波速度的计算公式,分析了设备内部波系的产生原因和运动规律,绘制了径向气波制冷机的理想波图,对各个端口的匹配进行了详尽的论述。 (2)对气波制冷机的单通道模型进行数值计算,模拟结果显示了通道内激波和接触面的运动过程,分析了气波制冷机端口夹角与激波运动位置的关系,研究表明,当激波运动到振荡管端部时,通道与端口呈现半开半闭状态为最优的匹配结果,最后编写端口匹配程序作为选择喷嘴间初始夹角的依据。 (3)对气波制冷流程进行了热力学分析,绘制了外循环式和过膨胀式气波制冷机的工作流程图,分别研究了压力、温度以及外循环量等操作参数对制冷效率和制冷温降的影响。研究表明,提高过膨胀度和入口气体温度都会导致制冷效率的增大,增大压比将会导致制冷效率的下降和制冷温降的提高,过高或过低的外循环量都会导致气波机制冷性能的严重下降。 (4)建立了气波制冷机的二维数值模型,采用数值模拟的办法研究了喷嘴、间隙、转子通道等结构对气波机制冷性能的影响。研究表明,适当增加喷嘴大小和通道长度可以提高制冷效率,制冷效率随着通道宽度和喷嘴后固壁段长度的增大呈现先增大后减小的趋势并存在一个最优值,采用斜喷嘴和前弯通道可以一定程度的优化气波机制冷性能。
[Abstract]:Gas wave refrigerator is a new type of refrigeration equipment which uses gas expansion to refrigerate. In this paper, the radial overexpansion gas wave refrigerator is taken as the research object. The internal flow field and refrigeration process are studied deeply by using numerical simulation and gas dynamics theory. The research results have a certain effect on improving the efficiency of gas wave refrigerator and optimizing the refrigeration process. Reference value. The main research contents are as follows:. 1) the working mechanism of gas wave refrigerator is explained by using shock wave theory, the calculating formula of shock wave velocity is deduced, the cause of producing wave system and the law of motion inside the equipment are analyzed, and the ideal wave diagram of radial gas wave refrigerator is drawn. The matching of each port is discussed in detail. (2) the single channel model of the gas wave refrigerator is numerically calculated. The simulation results show the motion process of the shock wave and the contact surface in the channel. The relationship between the angle between the port of the gas wave refrigerator and the moving position of the shock wave is analyzed. When the shock wave moves to the end of the oscillating tube, the channel and port show the best matching result in the semi-open and semi-closed state. Finally, the port matching program is written as the basis for selecting the initial angle between the nozzles. The thermodynamic analysis of gas wave refrigeration process is carried out, and the working flow charts of outer circulation and over expansion gas wave refrigerators are drawn, and the pressure is studied respectively. The effects of operating parameters such as temperature and external circulation on refrigeration efficiency and cooling temperature drop are studied. It is shown that the increase of overexpansion degree and inlet gas temperature will lead to the increase of refrigeration efficiency. Increasing the pressure ratio will lead to the decrease of the refrigeration efficiency and the increase of the refrigeration temperature drop. Too high or too low external circulation will lead to the serious decline of the refrigeration performance of the gas wave machine. (4) the two-dimensional numerical model of gas wave refrigerator is established. The effects of nozzle, clearance and rotor channel on the refrigeration performance of gas wave refrigerator are studied by numerical simulation. The refrigeration efficiency can be improved by increasing the nozzle size and channel length properly. The refrigeration efficiency increases first and then decreases with the increase of channel width and the length of solid wall behind the nozzle, and there is an optimal value. The cooling performance of air wave machine can be optimized to a certain extent by oblique nozzle and forward bend channel.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TB651

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