Performance Prediction And Study Of Blade Design Of Centrifugal Fan

Centrifugal fans are widely used in many fields such as industry, agriculture, mining, chemical engineering and building ventilation. The energy used for fans, blowers and compressor occupies a large fraction of the electric energy generated [1]. Thus, it is significant to reduce energy consuming with operation of high efficiency fans.To improve the performance of centrifugal fan, several type of centrifugal fans are studied in this thesis. Numerical simulation is employed to predict the performance and the inner flow field is researched. Based on the simulation, the research of performance improvement is carried out. The main research contents and results of this thesis are as follows:(1) A method of optimization design for the blade profile of a centrifugal impeller by controlling velocity distribution is presented in this thesis, and a plenum fan is successfully designed. The thickness distribution for NACA0010 is selected to get the wing section. The results show that after optimization, the boundary layer separation on the suction surface has been inhibited and the stability of plenum fan is improved. The static pressure and static pressure efficiency can be increased by 15.4% and 21.4% respectively.(2) A method of optimization design for the blade profile of a centrifugal impeller by controlling blade-loading distribution is presented in this thesis. The focus of the research is the blade-loading distribution at the middle part of the blade. The blade curve is determined by the blade-loading, and the blade-loading function is obtained by the average relative velocity and reference. The calculation shows that the total pressure efficiency can be increased by 16%.(3) Further design is carried out based on the model which is designed by blade loading distribution method. The inner flow is analyzed and a separation is found on the suction surface near the shroud. Then 3D blade are designed by change the inlet angle and the blade loading distribution. The simulation results show that the total pressure efficiency is enlarged and the inner flow is improved.