双螺杆压缩机CFD分析新方法的研究与应用

Exploring and Applying a New Method of Analyzing CFD of Twin Screw Compressor

针对实际当中阴阳转子之间的啮合间隙和转子与气缸内壁的间隙最大只有不到几十微米的情况,克服了Fluent动网格计算时为了尽量避免计算过程中出现负体积网格的现象而要将模型间隙放大至毫米级以便画出高质量体网格的不足点,探索出了一种替换动网格技术的新方法用于双螺杆压缩机的CFD计算分析,减小了用于CFD计算的流体域模型的间隙,将模型的间隙处理到微米级甚至为零,有效提升了螺杆压缩机的仿真精度与分析结果的可靠性。新的CFD计算方法中采用ANSA处理器划分双螺杆压缩机流体域的面网格和STAR-CCM+划分体网格的混合处理方式,利用STAR-CCM+中的Morphing技术实现双螺杆压缩机的流体动力学仿真。经过分析,新CFD方法的计算结果与理论和实际情况相符合,可用于指导螺杆转子型线的设计和优化。

For the case of the clearance between the male and female rotors and the clearance between the rotors and the cylinder is fewer than tens of microns actually, overcoming the shortcomings that it enlarged the model gap to the millimetre level in order to draw a high quality body grid when Fluent moving grid computing so as to avoid the phenomenon of negative volume grid in the process of calculation, a new method to replace the moving grid technology is explored, for the use of CFD calculation and analysis of twin screw compressor. With which, the clearance of the fluid domains for CFD simulation is reduced, and the gap between the model is processed to millimeter level or even zero, meanwhile, the simulation accuracy and reliability of the analysis results are effectively improved. For the new CFD simulation method, the surface meshes of screw compressor fluid domains are generated in ANSA and the grids of the domains are generated with polyhedral meshes and trimmed meshes in STAR-CCM＋, and the CFD simulation of screw compressors is carried out by Morphing in STAR-CCM＋ solver, whose analysis results are consist with theory and the actual situation, and can be used to guide the screw rotor profiles design and optimization after analysis.