非绝热毛细管快速计算方法

Fast Calculation Method for Modeling Non-adiabatic Capillary Tube

为了满足制冷系统仿真对非绝热毛细管建模在计算速度、精度、应用范围三方面的要求,提出了非绝热毛细管的一种快速计算方法。对非换热毛细管内流动可能出现的过冷、两相、过热三种流动区域分别建立物性的近似关系式,然后采用积分的方法得出不同流动区域长度的近似分析解。对于难以求解的两相区,通过拟合方法得到物性的近似关系式,并采用格林公式求解两相区的长度。对R134a,R600a,R12,R410A和R407C等工质的计算结果表明,提出的方法相对于分布参数模型的计算偏差小于2%,计算速度提高1000倍以上。提出的非绝热毛细管快速计算方法满足了制冷系统仿真的要求。

To meet the requirements on computation speed, accuracy, application range for modelling non-adiabatic capillary tube for re- frigeration system simulation, a fast calculation method for a non-adiabatic capillary tube is proposed. The approximation correlations for thermodynamic properties of refrigerant are proposed for subcooled zone, two-phase zone and superheated zone, respectively, and then the explicit approximate analytic solutions for the three zones are obtained using integral method. In the solution for two-phase zone, approxi- mation correlation for thermodynamic properties is obtained by curve-fitting method, and the length is obtained using Green＇s theorem. Case studies on R134a, Rr00a, R12, R410A and R407C show that the deviation between the predicted results of the proposed method and those of the existing distributed parameter model is less than 2% while the computation speed of the proposed method is 1000 times faster. The proposed method can meet the requirements for refrigeration system simulation.