【作者】 辛利；

【导师】 胡大鹏；

【作者基本信息】 大连理工大学 ， 化工过程机械， 2010， 硕士

【摘要】 射流振荡气波制冷机作为一种膨胀制冷设备,是通过射流振荡器生成振荡射流对一端封闭的振荡管周期性的射气,利用激波和膨胀波的运动,来实现冷热分离,到达制冷目的。射流振荡气波制冷机的突出优点是无需输入外加能量并且没有转动部件,只需简单的静密封。目前,射流振荡气波制冷机的研究还不成熟,其等熵制冷效率较低,不能满足天然气的工业生产要求。本文采用数值模拟和实验测试的手段对以音波振荡器为振荡源的射流振荡气波制冷机进行研究,主要工作和结论如下：(1)研究了附壁射流的流动特性,建立了附壁元件的数学模型,模拟了附壁射流的流场,重点分析了元件几何尺寸和操作条件对附壁射流的影响,结果表明：增大膨胀比和喷嘴宽度、减小位差等不利于射流附壁,改变入口压力和控制管长度对射流附壁的影响较小,设置分流劈有利于射流附壁。(2)研究了射流振荡气波制冷机的振荡过程,分析了气波机振荡过程中的流场以及控制管、振荡管内的压力变化,指出射流对中间振荡管的射气时间最短,提出了附加反馈腔结构,研究了操作条件和几何参数对射流振荡的影响,得出射流只在一定的几何尺寸和操作条件范围内才能稳定振荡。喷嘴过宽,位差过小和过大,控制管过长、过短、过宽和过窄,操作压力过大,射流均不能稳定振荡。射流在固定几何尺寸的条件下,存在最大可振荡膨胀比。膨胀比相同时,射流的振荡频率随入口压力的增大而增大,可振荡尺寸范围也增大。(3)研究了控制管长度和膨胀比对射流的振荡频率和制冷效率的影响,分析了控制管、振荡管内压力波幅变化,得到的结论有：射流的振荡频率随控制管长度的增加而减小,随膨胀比的增加而增加,增加的趋势逐渐变缓。控制管和振荡管内的波幅随着膨胀比的增加均增大,因此气波机的等熵制冷效率逐渐增大。中间振荡管的压力幅值小于两侧振荡管的幅值,附加反馈腔结构能增大射流射入中间振荡管的压力波强度,但与其它振荡管的波强度相比仍有一定的差距。更多还原

【Abstract】 Jet oscillating gas wave refrigerator, a kind of gas expansion refrigeration equipment, can separate the gas into hot and cold part by the motion of the shock wave and expanding wave using the jet oscillator to generate oscillation jet’s periodical injection into oscillating tube with one-closed end. So the refrigeration can be realized. The prominent advantage of this facility is that it doesn’t need extra energy supply and there is no moving part, just a simple static seal. At present, the isentropic refrigeration efficiency of the jet oscillating refrigerator is at a low level and could not satisfy requirement of natural gas’s industrial production.The performance of the jet oscillating gas wave refrigerator, using a sonic oscillator, is investigated by numerical simulation and experiments in the current paper. The main research work and achievements are as following:(1) The properties of wall-attaching jet flow are studied. The mathematical model is established to numerical simulate the flow field of wall-attaching jet flow. Emphasis is placed on analysis of effects on the wall-attaching jet flow of the element’s geometrical sizes and operating conditions. It is concluded that it is conducive to jet flow wall-attached to set the splinter, not conducive to increase the expansion ratio, the width of the nozzle and decrease the potential difference, of small effect to change the parameters (e.g. the inlet pressure and the length of the controlling tube).(2) The oscillating process of gas wave refrigerator is studied. The flow field of gas wave refrigerator in oscillating process and the pressure changes of the controlling tube and the oscillating tube are analyzed. The time of jet flow injecting to the middle pipe is shortest. So the jet flow oscillator with reaction cavity is proposed. Effects on the jet flow oscillating of the element’s geometrical sizes and operating conditions are studied. As a conclusion, the jet flow oscillates only in a certain range of geometrical sizes and operating conditions. The jet flow can not be stable oscillation if the geometrical sizes and operating conditions are not appropriate. There is a maximum oscillation expansion ratio of jet flow in the fixed geometrical sizes. At the same expansion ratio, the oscillation frequency of jet flow increases with the increasing inlet pressure, so does the size range of oscillation.(3) Effects on the oscillation frequency and the isentropic refrigeration efficiency of jet flow are studied. Pressure amplitude in the controlling tube and oscillating tube is analyzed. As a conclusion, the oscillation frequency of jet flow decreases with the increasing length of controlling tube and increases with the increasing expansion ratio, but the trend increases slowly. Pressure amplitude in the controlling tube and the oscillating tube increases with the increasing expansion ratio. Therefore the isentropic refrigeration efficiency of gas wave refrigerator increases gradually. Pressure amplitude in the middle oscillating tube is smaller than that in other oscillating tubes. The pressure wave intensity in the middle oscillating tube is larger while the reaction cavity added to the jet flow oscillator, but there is a certain gap comparing with pressure wave intensity in other oscillating tubes.更多还原