Learning Forum

[Weiqiang Liu]

Hi all,

I am trying to simulate soot combustion in diesel particulate filter. I get some results and I think I am very close to reasonable results. I can get just exactly the same soot concentration profile just like the picture in the paper below:

The maximum temperature is also consistent with in the paper. However, I can not get Y-velocity contour like in the paper below:

As you can see, there is a very obvious negative Y velocity at end of the channel. I think this is because soot is consumed at this position, which makes viscous resistance coefficients small compared to other part of the channel and gas is forced to flow through this small opening and further yield large filtration velocity.

However, in my model, the viscous resistance coefficient is indeed decreasing along axial position. However,  seems it's not small enough to produce such an obvious filtration velocity at end of the channel. I thought it might be something wrong with my equations of calculating viscous resistance for soot cake and porous wall. I checked those equations for many times. However, nothing works.

Can anybody give me some suggestions?

Best regards

Weiqiang