Internal Flow Analysis On The Diagonal Fan And Retrofit Design For The Rotor

The diagonal rotor usually matches with a volute. The efficiency of matching between the diagonal rotor and the volute has took important part in the efficiency of the system. However, the development of CFD methods has greatly promoted our understanding to flow mechanism, which in turn promotes the progress in design technique. In order to explore the effective approach of improving the performance of fan, its internal flow mechanism of diagonal fan is predicted and analyzed by numerical simulation and research of using an mature commercial CFD package in this paper. There are several parts about this paper:The first part presents the flow inside one diagonal fan coupled with volute with three-dimensional numerical simulation. Load distributions of blade, secondary flow and development of vortex are analyzed. The part also analyzed the internal flow of the volute, and the influence to the impeller. Detailed flow field information of the volute is gained. Results show that Due to the existence of volute and the influence of volute and impeller outlet, the secondary flow within the impellers are very complex. Non-uniform of the outlet regions and the mixing of different passages is the reason of inducing the efficiency low.The second part presents the application of skewed blade in the design of diagonal rotor. Numerical simulation results are analyzed and compared with the original diagonal fan. The results indicate that, the advantage of skewed diagonal rotor is to reduce the leak of tip clearance and the mixing of different passages. And so can effectively improve the blade performance and flow field. However because of single redesign goal, the skewed remodeled blade has good performance only in specific conditions. If improve the performance of the fan in all conditions, considering the influence of the volute interference, multiobjective optimization...