Numerical Investigation Of Gurney Flap Effect On Performance And Noise Of An Axial Flow Fan

Variable pitch axial flow fan adopts the method of adjusting the blade installation angle to adjust the flow rate.The adjustment efficiency is high and the adjustable flow range is wide.Therefore,it is widely used in the electric power field.However,its still include shortcomings such as high energy consumption and inefficient operation of high-efficiency fans.The improvement of its performance is of great significance for electric power production.Install Gurney flap(GF)on the trailing edge of the moving blade of the OB-84 axial flow fan.Using Gambit and Fluent to achieve meshing and numerical solution,study the effect of GF on axial flow fan performance,explore its mechanism to improve performance,and perform noise The research also used the static analysis module of Ansys to analyze wind rotor blades.For a variable-pitch axial fan with guide vanes,the effect of three series of GFs configured at the trailing-edge of blades on the performance and dynamics is numerically investigated,and the aerodynamic noise is predicted.Simulated results show that GFs increase the total pressure rise of the fan,and the higher the GF height,the more notable the lifting capacity.The working point of the highest efficiency moves toward the large flow rate.GF0.5-100 extends the high-efficiency scope and increases efficiency by an average of 2.09%;GF2-50 R raise efficiency by an average of 1.12%.The GF0.5-100 and GF2-50 R can increase the efficiency of the large flow side under blade pitch angle of 29°,32° and 35°,they also expand the flow adjustment range of the fan.After implementing a GF,the dynamics in the impeller varies apparently.Compared with the original fan,a secondary tip leakage vortex generated at the blade tip aggravates the leakage loss;a pair of shedding vortices generated in the downstream of trailing edge promotes the pressure difference between suction and pressure surfaces.The prediction with Large Eddy Simulation(LES)indicates that GFs heighten the aerodynamic noise of the fan,GF0.5-100 and GF2-50 R increase the SPL by 12 d B and13 d B.Although the GF0.5-100 and GF2-50 R are preferred choices for such axial fan,some necessary measures should be taken to reduce the acoustic noise in practical applications.After the installation of GF,the load and deformation of the fan blade surface are reduced.