Development And Design Of A Vehicle Air Filter Based On CFD Technology

The aim of this project is to design a SUV air filter.Compared with the same series of models,the car has large volume,strong performance index and high requirements for an air intake system.The rated air flow of the air filter is as high as 9.7m3/s,and the ash capacity is increased to 180g.In this thesis,by using CFD simulation and experimental techniques,the shell structure of the air filter is optimized,and the double-layer structure filter element and other components are novelly developed to ensure the index requirements of the air filter.Firstly,according to the model parameters and space of the engine,the preliminary design of the air filter is completed by the empirical formula.Then the CFD simulation technique is used to analyze the flow field,velocity and pressure.The finite element optimization analysis is carried out for the corner of the upper shell and the position of the filter element.The structure of the corner of the upper shell is modified to reduce the larger flow vortex radius of the air flow at the outlet pipe.The test results of sample performance show that the pressure drop is below 2.65kPa,and the error between the test results and the simulation results is 3.7%;the initial and final filtration efficiency are 98%and 99%.Secondly,in order to give full play to the ash storage capacity of a non-woven fabric and the filtration efficiency of the filter paper,the double-layer filter element structure with the non-woven fabric at the front and the filter paper on the back is adopted.Based on CFD finite element analysis and a series of experiments,the original Ahlstrom SK3350 filter paper with 41mm folded width is adopted to ensure the filtration efficiency performance.A 3LANK1250 non-woven fabric with the porosity of 98%and the average aperture of 158 ?m is selected to improve ash capacity.Moreover,the thickness of 8mm non-woven layer is optimized,and the pressure is reduced to 2.65kPa.Four durability tests were carried out for the optimized product samples,including high-low temperature vibration,high-temperature,low-temperature and high-low temperature cycles,which verified that the connection strength of filter paper layer and non-woven fabric layer met the product requirements.The results showed that the initial filtration efficiency of all samples was higher than 98%,while the final filtration efficiency was higher than 99%,and the ash content was more than 190g,all of which met the product requirements.In order to give full play to the advantages of the ash capacity of the new filter element,the polyurethane sealant foaming process was used to produce the sealing ring of the filter element in the plastic sealing process of the double-layer bimetal filter element,which improved the sealing performance and reduced the production cost;in order to ensure the molding quality of the air filter shell,the complex structure part of the upper shell body was separated into small parts,which reduced the difficulty of the mold and inj ection molding,and then the Moldex 3D software was employed to analyze the injection molding process such as the upper shell to improve the molding quality.Finally,the overall performance test of the assembled new air filter was carried out,indicating that it reached the use index of the whole machine factory and was ready for the massive production.