Design Method And Numerical Simulation For Volute Based On Control The Distribution Of Circumferential Cross Section

As a key component of centrifugal fan,Volute has two functions:first,collecting fluid from impeller;secondly,converting kinetic energy from high speed fluid to required potential energy.The volute profile is the most important part in the volute design process.The volute profile represents the overall shape of the volute,which is the boundary that limits the fluid movement inside the volute.At the same time,the volute profile also determines the position of the volute tongue and the size of the clearance between volute tongue and impeller,which has a great influence on the performance of centrifugal fan.Currently,the volute design are based on constant circulation distribution assumption or constant velocity distribution assumption.However,there is a great unsteady flow inside the volute,which means that the flow parameters on the volute circumferential section and the volute inlet are unevenly distributed.So,the theoretical assumptions in the design process often do not conform to the actual situation.Secondly,the currently design method of volute profile lacks the control of the cross-section area distribution and can not determine the position of the volute tongue and the size of the tongue clearance.In this paper,a forward-curved blades centrifugal fan had been taken as the research object.A numerical optimization design method was proposed to control the distribution of circumferential cross-sectional area.Under the condition of only changing volute,This method combines the optimization algorithm and numerical simulation in order to achieve maximum total pressure and not reduce fan efficiency.The design of volute profile was parameterized.Using 3D drawing software and Fluent,many groups of models had been established and their performance had been simulated.According to the simulation results,the design parameters of the volute profile had been optimized.Finally,it was found that the reasonable distribution of the circumferential cross-section area can obviously improve the performance of the fan.The optimized volute improved the flow condition,increased the airflow velocity and reduced the airflow angle at the outlet of the fan impeller.Eventually,the fan total pressure was increased by 8.46%,the total efficiency was increased by 1.15%.Noise prediction of fan before and after optimization was carried out.The broadband noise of the two sets of fans was compared with FLUENT.And the near and far field noise was compared with indirect boundary element method respectively.From the simulation results,the optimization of the volute profile effectively reduced the aerodynamic noise of the fan.