Design and test of an axial fan for a subsonic wind tunnel

According to the requirement of the subsonic wind tunnel built by China Aerodynamic Research and Development Center, the aerodynamic design of the axial fan was completed. The Mach number of the test section corresponding to the design point of the fan is 0.7, which has the characteristics of large pressure rise, small flowrate, low blade Reynolds number and complex operation conditions. In the design process, the axial velocity of fan channel and the pressurization capacity of fan are increased by selecting large hub-tip ratio. And the more rotor blades meet the two-dimensional flow characteristics of blade airfoil as much as possible. In the meanwhile, the of controlled vortex method is used to adjust the swirl velocity of the blades, control the flow separation of the blade root, increase the work capacity of blade tip and enhance the aerodynamic efficiency of the fan. The test results show that when the fan speed reaches 7600 rpm, the Mach number of blade tip is 0.72, the fan pressure ratio is 1.08, the fan efficiency is 85%, and the Mach number of test section gets 0.7, which meet the design target. The development of this fan has preliminarily explored the aerodynamic performance of the axial fan at high rotate speed, broken through the design limit that the Mach number of the blade tip of the conventional axial fan is not more than 0.5, and realized a higher pressure ratio of the fan (1.08) and a higher aerodynamic efficiency of the fan under the condition of low Reynolds number of the blades, which provides an effective reference for increasing of the axial fan pressure rise (pressure ratio) in the future.