双螺杆膨胀机泄漏过程的数值模拟与分析

Numerical Simulation and Analysis of Leakage Process in Twin Screw Expander

利用PROE软件建立双螺杆膨胀机的三维几何模型并测量计算出基元容积、进气孔口面积、泄漏面积随阳转子转角的变化,进行几何参数分析.然后以几何参数为基础,根据能量和质量守恒定律建立热力学模型,模型综合考虑了进气节流、泄漏和实际气体状态方程.选择不同的运行参数仿真分析基元容积中工质质量,通过各泄漏通道的泄漏质量随转角的变化以及对螺杆膨胀机内效率的影响.研究发现,进气和膨胀初期的泄漏是影响螺杆膨胀机内效率的一大因素,接触线和齿顶与机壳内壁是螺杆膨胀机主要的泄漏通道,进气压力的提高和转速的减小都会增加泄漏质量.

A 3Dgeometry model of a twin screw expander was developed using PROE to measure and analyze geometric parameters such as groove volume,suction port area and leakage area as a function of rotation angle of the male rotor.Then,based on the geometry model,a thermodynamic model was developed using the continuity and energy conservation equation and taking the suction loss,leakage loss and real gas effect into consideration.Based on the model,the mass flow rate through inlet port and leakage path as a function of rotation angle of male rotor as well as the effects of expander inlet parameter and operating parameter on the performance of the expander was analyzed.It is found that leakage in the suction process and the early stage of expansion process is one of the main factors affecting the internal efficiency,leakage through contact line and rotor tip-housing clearance is the main leakage path,and that the increase in inlet pressure and decrease in rotor speed would lead to the increase of leakage mass.