混合工质在制冷机节流元件毛细管中的流动特性

FLOW FEATURES OF MIXED-REFRIGERANT IN CAPILLARY TUBES OF COOLER THROTTLING ELEMENT

可用于天然气液化的深冷多元混合工质节流制冷技术由于其固有的优点以及其制冷温区跨度大的特点 ,近年来得到了前所未有的重视和发展。随着这项技术的不断成熟 ,对混合工质在深冷制冷机节流元件内的流动特性的研究也显得日益重要。纵观现有的众多节流毛细管的研究文献 ,内容主要涉及普冷工质的流动特性 ,而且其中大多采用的是均相模型。而深冷多元混合工质由于其本身的特点 ,与普冷工质有着很大的不同。为此 ,文章旨在研究混合工质在毛细管内的流量特性 ,尝试使用了分相流动模型来计算深冷多元混合工质在绝热毛细管中的流量特性 ,建立了深冷混合制冷剂在毛细管中流动的控制方程 ,并依此编制了计算程序 ;同时搭建了深冷混合工质在绝热毛细管中流动特性实验台 ,进行了深冷多元混合工质在绝热毛细管中的流动特性实验研究。理论计算结果与实验结果符合度较好 ,其偏差均在 10 %以内 ,基本满足了工程上的需要 ;

The throttling refrigeration technology with cryogenic mixed-refrigerant, which can be used for gas liquefaction, obtains attention and development more than ever before in the recent years since it has the inherent advantages and the characteristics of big refrigeration scope. As the technology becomes more and more mature, the study of flowing features in the throttling element of the cooler becomes more and more importance. In the large existing documents about throttling capillary tubes, they mainly describe the flowing features of average refrigerants using mostly the homogeneous phase model. But the cryogenic mixed-refrigerants much differ from the average refrigerants. The purpose of the article is to study the flowing features of the mixed-refrigerants in capillary tubes. Using the separated flow model, the flow rate of the cryogenic mixed-refrigerants is calculated in the adiabatic capillary tubes. The control equation is set up for the cryogenic mixed-refrigerants flowing in the capillary tubes. And the computer program is made based on the equation. Also, a test stand is established to study the flowing features of the cryogenic mixed-refrigerants in the adiabatic capillary tubes, and the testing study is conducted. The theoretically calculated results fit the test results well. The difference is no more than 10%, which meets the engineering requirements basically. Also, the influence of the major parameters, such as the structure of capillary tubes and the composition of the mixed-refrigerants etc., on the flow rate of the refrigerants is discussed.