Discussion Forum

I am working on a project that requires me to find the residence time distribution of flow through a porous electrode. Due to the presence of other regions containing only fluid, I made the electrode geometry with the “Free and Porous Media Flow” module, and was able to find the fluid flow rates and streamlines. To find the RTD, I’ve tried to use both the “Transport of Dilute Species” and “Transport of Dilute Species in Porous Media” to mimic the effect of an injector used to find residence time, placing a probe at the outlet to monitor outflowing concentration.

The problem I keep running into is that for some reason the concentrated region doesn’t move with the streamlines of the fp module. Increasing the time of the simulation or prescribing a higher flow rate does nothing, the concentrated region will not move and I can’t find the RTD. It just stays there at the opening. I’ve checked all the boundary conditions, made sure the velocity field is input from the fp module. I’m sure there’s something really simple I’m missing, but can’t find any tutorial combining these two modules.

Can anyone help solve this problem, or suggest an easier way of finding the RTD using the flow field?