Full-3D Numerical Investigation And Optimized Design On The Centrifugal Fan

Centrifugal fans are widely used in national defense and industry. It plays an important role in the national economy and daily life. So, studying and optimizing the centrifugal fan can optimize the energy distribution and reduce the emissions. In this paper the research was instituted under a research project of the CSIC. The numerical simulation was used to study a marine's centrifugal fan, and the results were compared with the experiment. Then the aerodynamic performance of the impeller and volute was optimized. The works were mainly done in the following aspects:(1)Numerical simulation on the original centrifugal fan. The original fan's structure and experiment system were introduced. Then the grids' division and numerical calculation's settings were done, and the simulation results were compared with experiment to be verified. So the main features of the original fan's flow field were analyzed and the calculation results indicate that the aerodynamic performance is not well and the flow separation in the impeller is very serious.(2)Optimization design of 2D blade. In order to improve the aerodynamic performance of the original centrifugal impeller, a design method of 2D blade profile on the impeller has been proposed. And the best efficiency of the impeller was selected through numerical simulation. The numerical results show that the efficiency and total pressure rise of the impeller, which is obtained through this method, are greatly improved. And the whole fan's efficiency is also improved greatly. The analysis of flow field shows that the flow separation in 2D- optimized impeller is greatly weakened and the flow field is optimized.(3)3D blade optimized exploration. On the basis of the 2D blade design, the 3D blade was explored. The 3D blade exploration mainly consists of two aspects, namely 3D blade profile optimization and the stacking line's sweep and lean. The 3D blade profile was optimized with the optimization objectives of the impeller's efficiency and total pressure rise. The results show that the 3D blade makes the performances of either the impeller or the whole fan is greatly improved. Stacking line exploration shows that lean blades and swept blades have a significant impact on the centrifugal fan's performance, and the impact of the combined blade is not a simple superposition by the single swept blades and lean blades.(4)Analysis of the volute's width and the impeller's position in axial. The results of whole fan's simulation show that both the impeller's axial position in the volute and the volute's width have a significant impact to the fan's performance. And there is an optimum combination of the two parameters. The fan, with the best combination of the impeller's axial position and volute's width, can further improve the aerodynamic performance of the machine.