Optimization of the tip profile of orbiting scroll in an asymmetry suction chamber scroll compressor

Abstract The scroll compressors with asymmetrical suction chamber have large discharge loss, as the pressure in outside chamber is far larger than the discharge pressure when the discharge process begins. It is necessary to optimize the scroll profile around the discharge port to reduce the discharge loss. The theoretical method is to redesign the tip profile to obtain the same volume ratio of outside working chamber with the inner working chamber. However, as it is difficult to predict the discharge loss through the flank gap in discharge chamber, the optimum design cannot be obtained. In this paper, we establish an optimization platform based on the CFD method. The profile of orbiting scroll tip is parametrized with CAD software, then the CFD calculation will be done and the performance parameters will be extracted. The MOST optimization algorithm is used to search the best performance parameters and control the parameterized value of scroll profile. After iterations, the best profile with the modification angle of 66.3° was obtained. Compared to the original model, the volumetric efficiency of the compressor increased by 4.11%; and the isentropic efficiency increased by 4.91%. Afterwards, the flow field are analysed to study the characteristics of the optimized scroll compressor. The results show that the backflow, the secondary vortex in discharge chamber and the discharge mass flow pulsation were reduced, which led to the decrease of the discharge loss and the improvement of the isentropic efficiency.