Comparative Study of Free Vortex and Random Vortex in the Design of Wind Tunnel Axial Fan

The design methods of axial flow fan mainly include free vortex design method and random vortex design method. The random vortex design method and free vortex design method were used to design aerodynamic parameters of two fan systems, and then the performance of these two fan systems was compared by numerical simulation. In the numerical simulation, the random vortex method and free vortex method are applied, respectively, based on the fan design parameters given by the acoustically guided wind tunnel fan section, and the physical model was established, the numerical simulation comparison study was conducted for the two sets of fan systems. The comparative analysis of the numerical simulation results shows that compared with the free vortex method, the fan designed by the random vortex method can reduce the local separation of tip and root of the blade, and the axial velocity distribution of fan blade and fan section outlet can be more uniform, and there is a certain increase in fan blade efficiency. These results verify that the design method of random vortex fan is feasible in large wind tunnels, especially in wind tunnels with aerodynamic noise reduction requirements, and can provide powerful conditions for optimizing aerodynamic and acoustic performance of the fan.