Analysis Of The Structure Characteristics For The Ceramic Wall Flow Filter

Ceramic wall flow filter is an effective carbon particulate matter purification device on the diesel engine vehicle. Along with automobile emission standard request more strict, in the craft micro-structure and the performance, strengthen requirement gradually, achieves higher efficiency, lower exhaust resistance.Ceramic wall flow filter model includes many narraw micro channels. The usual flow field analysis on the computer consider the entire filter as porous zone, can not get characteristic parameters of the micro channel flow distribution and PM deposition density. This article focuses on interior flow quality analysis of the long and narrow micro channel selectedfour 1/4 channels and the four porous walls as the calculation, analysis of micro-channel wall on both sides of the flow parameters, seek optimum value of the micro channel structure size. Mainly consider of three kind of models which width of channls respectively is 1.2mm, 1.0mm, 0.8mm, using the FLUENT software, the three dimensional hexahedron body mesh structure, has carried on the simulation with k-εturbulence model, analysis on its static pressure field, velocity field and the carbon partical density field.Compution results of the different width of side micro channel indicate that half width of the 1.2mm model has low exhaust resistance, good carbon pellet deposition characteristic, then selected half width of the 1.2mm model. Followed by half a length of 1.2mm on the model selected of the inlet velocity of 20m/s, 30m/s, 40m/s for simulation respectively, shows that 20m/s model with a better flow characteristics. According to the above obtains, certain structure size filter can only obtain the ideal result under certain flow quality.Increases the width of channel and the item of number to be advantageous to the filter efficiency enhancement. In a certain cross-sectional area, number of filter's item with channel width and the wall thickness of the square is in reverse proportion. Therefore, to improve the filter performance to increase the number of item or to increase the width of side is contradictory. When can not get both of them, increase an item of number to become the usual choice, the question is the enhancement of the technological requirement.The current numerical simulation method provides convenience to analysis the question, but has many insufficiencies to the multi-parameter optimization.