Design And Optimization Of High-speed Centrifugal Compressor For Vehicle Fuel Cell

With the deepening pursuit of clean energy vehicles,fuel cells have gained the attention of scholars at home and abroad due to the advantages of high energy conversion rate,zero pollution of the generated material,and wide range of sources.Based on the requirements of pressure ratio and efficiency of inlet system for on-board fuel cells as well as the requirements of space and quality of vehicles,centrifugal presses have become the first choice for fuel cell inlet system for on-board fuel cells.The performance of the centrifugal compressor has a very important impact on the performance of the fuel cell,and the design and optimization of the high performance centrifugal compressor is of great significance.In this paper,the pneumatic design of the compressor is based on the requirements of the centrifugal compressor for automotive fuel cells.The established centrifugal compressor model is optimized to further improve the performance of the compressor and obtain a design model with better performance.The specific work is as follows.The centrifugal compressor design and simulation were completed.According to the requirements of the vehicle fuel cell,the centrifugal compressor was designed by using Compal,Ax Cent and Turbo Grid for 1D design calculation,3D modeling design and mesh division,and the designed centrifugal compressor was simulated by using CFX software to obtain a compressor model with pressure ratio of 2.05 and isentropic efficiency of 77.53%.The simulation results were analyzed and found that the overall flow of the compressor is stable and meets the design requirements.The causes and effects of the loss model were analyzed,and the efficiency was found to have room for further improvement.Optimized design and simulation of the pressurizer was completed.In order to reduce the losses in the initial model and improve the operation efficiency,the initial model was optimized by Turbo OPT software with one-dimensional multi-parameter optimization,the optimization condition was the stability of pressure ratio,the optimization objective was the optimal efficiency,the one-dimensional optimized model was optimized by three-dimensional modeling design,and the optimized model was simulated and calculated by CFX.Through analysis and comparison,the optimized pressure ratio is kept stable,the overall efficiency of the compressor is improved by3.96%,the leakage inside the compressor is weakened,the entropy increase is reduced,the jet wake is weakened,and the losses appear at a later position,and the overall flow is improved.The effects of the size of the top clearance and the length of the diverging blades on the performance of the compressor were investigated.By setting four different values of the top clearance,it is found that with the reduction of the top clearance,the internal flow field of the centrifugal compressor is significantly improved,and the overall performance of the compressor is also greatly improved.In the range of reasonable length distribution of the diverter blade,four different lengths of diverter blades are modeled,and with the increase of the diverter blade length,the overall performance of the compressor decreases,but the decrease is not obvious,and the impact on the aerodynamic performance of the compressor is not significant.