Hi all,

I am doing a soot cake combustion transient simulation with fluent. I can get everything including temperature magnitude, soot concentration and oxygen concentration right except velocity contour.

I found the velocity contour is very sensitive to permeability namely viscous resistance of soot cake. I tried to draw the plot of resistance coefficient varying with consumption of soot and found almost linear relationship. However, I am expecting exponential decrease of resistance with the consumption of soot. 

I read a lot of papers. Those authors just assume spherical particle composition for the porous soot cake. Can anybody give me some suggestions on how to calculate porous soot cake permeability? 

Best 

Weiqiang