Study on the Internal Flow Characterisitics of Small-size Axial Flow Fan

In order to study three-dimensional flow fields characteristics of small-size axial flow fan,fans of 5 blades and 7 blades are simulated respectively using Fluent software RNG k-e turbulence model and steady flow functions.Static characteristics and the internal flow performance of the two fans are analyzed comparatively based on the numerical simulation results.The conclusions are as follows: the pressure does not change significantly within(0.006m3/s,0.0105m3/s),but outside the range pressure gradient decreases gradually with flow rate increasing;the inlet total pressure increases gradually after that lowers firstly,which occurs in increasing abruptly in 1/2 chord length;with increasing of radius,static pressure increases in the tip clearance;In inlet suction side,static pressure,vorticity magnitude and speed are very small.The velocity increased gradually and blade tip vortex appears near the casing and suction surface after air flows into channel and the aerodynamic noise is very sensitive to the tip vortex which impacts the pressure surface of the close blades.