Numerical Simulation For Internal Flow Field Of G4-73NO.8D Centrifugal Fan Based On Parametric Modeling

With the improvement of computer technology and calculation method, thetechnology of CFD has been widely used in many fields. The CFD numerical simulationcan provide abundant information of the flow field and the reliable basis for the designand improvement of fluid machinery. In addition, the CFD numerical simulation hasbecome an important means of internal flow study because there are lots of difficultiesin experimental measurement of fan’s internal flow field. Therefore, the numericalsimulation of G4-73centrifugal fan is performed by using the commercial CFDsoftware FLUENT in the article. Then, velocity vector diagram, total pressurenephogram and dynamic pressure nephogram of different cross section inside the fanare obtained. Based on the analysis of pre-processing software GAMBIT and themechanism of numerical calculation software FLUENT, parametric numericalcalculation platform is developed by GAMBIT, FLUENT and VB programminglanguage. this platform can realize the parametric modeling and FLUENT numericalcalculation, which greatly shortens the time of geometry modeling and grid division inthe process of numerical simulation.The influence of different collector structure on the performance of the fan is studied.Fans with6different collector structure are simulated, and the blower’s total pressureand velocity field are analyzed. The results show that the fit between the cone-arccollector and whole machine is best, and that between cylindrical one and wholemachine is worst.Three main impeller parameters of the fan, blade number, blade outletangle and outlet width are selected, and the orthogonal experiment is designed. Variouscombinations of orthogonal experiments are simulated by the parameterized numericalcomputing platform, and the target value of total pressure is calculated, then thevariance analysis of orthogonal experiments is done. The conclusion shows that theoptimal combination scheme is that leaf number16, blade mounting angle46°, and theimpeller outlet width203mm. Finally, the numerical simulation of this scheme isverified, and the research shows that this optimal scheme can perfect the inner flowfield of fan.