30 December 2018
I really appreciate your super clear illustration!! Actually, my confusion came from a paper review when I tried to reproduce the simulation results with fluent.
The object of the simulation is called diesel particulate filter, namely DPF. you might know this device. it's a particle filter of diesel engine. below is the real picture of this device.
the square straight channels of DPF are open and plugged alternatively. The exhaust gas of diesel engine flows into the filter from open channels and is forced through the porous wall. Ultimately, exhaust flows out of the filter from the other end of the filter and the soot particles are left in the porous wall. The picture below shows the working principle of DPF.
After the mass of soot deposited in the filter reach some predefined limitation, the soot has to be burned out which is called regeneration. I am trying to simulate this burning process in DPF with fluent. In conclude, it's a simulation case related to flow field, porous media combustion. Ok , above is the background.
I found a paper published on Chemical Engineer Science which took a pair of the channels as 2D computation domain. Below is the computation domain in this paper.
Except inlet, outlet and interface of the porous media, all other boundary conditions are WALL in the paper. There are two aspects that confuse me very much.
1. Since it's a square straight channel, then it can not be simplified into 2D model like you said, right?
2. In a single channel of the DPF, all four walls are porous media, which makes all of the wall deposited with soot cake. Then why is the lower wall has porous soot cake on it and the upper wall is set to WALL boundary condition?
I sent an email to the author to express my confusion but did not get any reply.
have you ever met cases like this?
thanks very much!