Performance Research And Optimization Design Of Engine Cooling Fan With Deflector

In recent years,the power of automobile engines has been increasing,the cabin layout has been more compact,and the requirements for engine cooling systems have become higher and higher.The fan is a key component of the car engine cooling system.On the one hand,the fan with good performance can improve the working efficiency of the engine cooling system and improve the dynamic performance of the engine.On the other hand,it can effectively reduce the engine compartment and ambient noise,thereby improving the comfort performance of the vehicle.Therefore,improving the performance of the fan can effectively improve the overall performance of the car.The development of fan design theory and the results of fan performance optimization in recent years were firstly introduced in this paper.The fan noise reduction method and the generation mechanism of fan noise were summarized.The development of fan computational fluid dynamics theory and aeroacoustics theory were introduced,the CFD software-ANSYS CFX features and simple applications were introduced.Based on computational fluid dynamics theory and aeroacoustics theory,a CFD/CAA simulation method is used to simulate the engine cooling fan of an automobile,the standard air volume and the noise value of the cooling fan are obtained.Compared with the experimental results,the error is less than 5%,it is proved that this fan model and simulation calculation method can be used for subsequent calculation and research.The appropriate shape of deflector was selected to be added to the original fan model,the structure of the deflector was parameterized,and the parametric equation for the section curve of the deflector was established;the orthogonal test was designed,and in this test,the thickness,number,forward rake angle,and back rake angle of the fan deflector are the five factors of the test,the cooling fan standard air volume and noise value are evaluation indicators.Each test model is solved by simulation and each result was analyzed,thus the influence of the deflector'sstructural parameters on the fan performance was obtained.Combined with the influence of the deflector various characteristic parameters on the fan performance,the Box-Behnken test was designed to select three characteristic parameters of the deflector with the greatest influence on the fan performance as the three factors of the test.The standard air volume of the fan and the noise value at the air inlet monitoring point are the response value.The multiple linear regression equation was established and it can be used as the proxy model,the relationship between the three characteristic parameters of the fan deflector and the fan performance evaluation index is fitted,and the proxy model is used to optimize the structural parameters of the deflector.The optimized fan air volume increased by4.55% and the noise value decreased by 5.8dB.In this paper,the structure of the deflector added on the original fan model is simple,the noise reduction effect is remarkable,and the structural strength of the fan can be effectively improved.It has engineering practice value and provides a theoretical basis and method for the research and optimization design of the low noise axial flow machine.