Research And Optimization Design Of Low Noise Of Engine Cooling Fans Blade

The intelligent and networked automobile makes the automobile parts more and more complete.The installation of parts such as exhaust purification device and so on leads to a more complicated and compact layout of the front cabin.There is limited space for the arrangement of cooling systems.At the same time,people's pursuit of dynamic performance makes the engine power increase continuously,increase the working load of cooling system,and increase the noise.By studying the working mechanism of the cooling fans,it is found that the blade shape has an important influence on aerodynamic noise performance of the cooling fans.Based on the theoretical basis of hydrodynamics and aeroacoustics,this paper studied the simulation method of aerodynamic performance and noise performance.The experimental results of the aerodynamic performance and noise performance of the cooling fans were compared with the simulation results of the original model,the accuracy of simulation method was verified,and provided the basis for optimization of blade structure.This paper introduced the Bezier curve,and established the parameterized model of the cooling fans based on the Bezier curve.The aerodynamic performance and noise performance of the parameterized model were simulated,and the experimental results and the simulation results of the aerodynamic performance and noise performance of the cooling fans were compared with the simulation results of the parameterized model,and the accuracy of the parameterized modeling method was verified and provided basis for parametric design of other axial flow machines.With five unequal sections as test factors,inner chord length,maximum relative deflection and maximum relative radius were used as test levels,the total sound pressure level of the monitoring point noise and inlet of the cooling fans were the evaluation index,the orthogonal test was arranged with the standard air volume of the cooling fans and the total sound pressure level of the monitoring point at the inlet as the evaluation index.The influence of the length of internal chord,the maximum relative deflection and the maximum relative radius on the performance of cooling fans was studied.On the basis of orthogonal test,the Box-Behnken experiment was designed.In order to reduce noise value,RSM method was citing to calculate the regression equation,to determine the optimal structure parameters of the blade.Finally,the noise value reduced 8.4% on the basis of satisfaction of flow requirements.In order to further reduce the aerodynamic noise of the cooling fans,a new cooling fan structure,namely the wavy blade structure fan was proposed in this paper.The influence of wave structural parameters on the performance of cooling fans was studied by orthogonal test.According to the test results,the optimal design was choosen.Compared with the non-wave structure cooling fan,the noise value of the monitoring point was reduced by 8.4%,while the air volume increased slightly,the design achieved the design goal,had the practical development value.It can provide theoretical basis for producing high performance and low noise cooling fan in industry.