[smhosseini]

Hi,
I'm going to model gas flow in porous media. Gas reacts with porous solid and volume of porous solid increases. I want to solve the continuity equation for gas and porous solid, Darcy's momentum equation and energy equation. When I have not considered the volume expansion, I have used finite volume method with structure grid, but now, each cell of my grid has spacial volume at each time.
I have an equation for rate of volume expansion and I assumed the expansion occurs only in one dimension.
The attached figure shows may grid. Does anyone have any better idea for this problem?
Does anyone now the best way for discretization of equation on attached grid?
thanks in advance.