Study On Aerodynamic Performance And Aerodynamic Noise Of Cooling Fan With Guide Ribs

Axial-flow fan is widely used in modern automobile because of its light weight,low cost and simple structure.As an important part of the automobile,its performance will directly affect cooling,power and noise of the engine.So the development of low-noise,high-efficiency cooling fan has become an important issue.With the development of computational fluid dynamics,simulation technology CFD has been adopted by more and more manufacturers.CFD simulation technology can not only be used to predict the fan aerodynamic performance and fan noise level,but also can be used to capture the complex flow field changes of pressure and velocity,which will be used to guide the fan design.This paper introduces the performance index and testing device of the fan,and then it introduces the numerical method of the aerodynamic performance and the aerodynamic noise of the fan,as well as the selection of relevant parameters and turbulence models.The simulation results are compared with the experimental results,the parameters such as pressure and velocity after the calculation are analyzed,at the same time,the simulation model and the calculation method are validated,which can be used to guide the design and optimization of the fan structure.In this paper,a no-rib fan is compared with a guide rib fan,and the difference between these two was analyzed based on method of local dynamics diagnose.The results show that the performance of the fan with the guide rib is better than the other one.The circumferential vorticity distribution of the no-rib fan is not reasonable,and the distribution of the negative circumferential vorticity in the region of the guide ribs fan is obviously reduced,the physical source of bad flow is control.It is proved that the guide rib can effectively cut off the negative circumferential vorticity,improve the flow field distribution,and realize the design purpose of improving the efficiency and reducing the power consumption.Finally,the influence of the structure and parameters of the guide rib on the performance of fan is analyzed.The results show that: 1)The fan guide ribs with smooth structure can cut off the negative circumferential vorticity of the fan more effectively,so that the efficiency of the fan is highest,the power consumption is smallest.2)The thickness of the guide rib has a significant effect on the aerodynamic performance of the fan.The smaller or larger thickness not only affects the mold design,but also cannot effectively cut off the negative circumferential vorticity and reduce the static pressure efficiency of the fan.Only when the fan guide rib is designed at the appropriate thickness.The guide ribs can cut off the negative circumferential vorticity effectively,and the aerodynamic performance of the fan is optimized.