CFD modelling, rotary compressor, overset mesh
Full 2D and 3D unsteady CFD simulations are gradually replacing the widely used lumped parameters simulations for rotary compressors. Lumped parameter models predict the overall thermodynamic processes; however, they cannot reveal the spatial and temporal variations in the working chamber and account for complex fluid interactions and losses. The complex and continuously deforming working chamber geometry is challenging for CFD. The overset method has been implemented here for the simulation of a 2D Coupled Vane Compressor (CVC). The method was compared to a dynamic mesh formulation using a remeshing technique and has shown; (1) it is 3-4 times faster computationally and (2) capable of modelling tight clearances not possible in the dynamic mesh approach and are difficult, if not impossible to model using the lumped parameter models. The CFD results revealed complex fluid interactions inside the chamber, accounted for leakage and can be used to optimize the CVC designs further.