Inner Flow Analysis And Performance Optimize Of Air-Condition Axial Flow Fan

Research the 3D flow field of the impeller of the original and the new designed axial fan used in air-condition respectively, using experiment and numerical simulation. The experimental study was based on data obtained using an outer characteristic platform of fan, while the numerical simulation adopted Fluent, the 3D numerical simulation code. This paper is divided into two parts: The first part simulates the inner flow field using 3D time-averaged N-S equation and standard K-εtwo equation turbulence models, using axial fan system used in air-condition as computational model, and optimized the impeller based on the original. The results of performance experiments and numerical simulation show that the new designed impeller using CAD/ CFD technique satisfies the design request, raises the breeze quantity, and lowers the voice. It can provide basis for improving design of the air condition fan system, application of different leaf fan, and further research. Analyze the effect of the static pressure distribution turbulence viscidity of the blade surface, and the rule of the near wall flow structure and loss in the flow passage, based on the numerical simulation. Results of the numerical simulation show that the new designed impeller improves the inner flow structure, reduces the loss, speeds up the attenuation velocity of the tail vestige, and the flow distribution is more reasonable. The second part studies and analyzes the tip leakage flow and tip vortex. Tip clearance vortexes appear near to the suction surface of tip region, and develops to the downstream direction pointing to the pressure surface of the adjacent blade, while the development direction of the clearance vortex is opposite to the rotational direction of the impeller; Tip vortexes appear near the suction surface in tip region due to the interaction of main current in the flow passage with inhaling flow from the outside of the tip region, and develop continuously, then move to the downstream following the suction surface, also they move to the pressure surface gradually. From the former edge of the tip region to downstream, tip vortexes spread gradually, and develop to the downstream along a bias which is contrary to the rotational direction of the impeller.