Modeling a water seal boundary condition for biomass gasifier
 

Hi!

I am working on simulating a biomass gasifier in FLUENT. I am doing so using the Euler-Euler multiphase model and have looked at various multiphase tutorials to understand what are the methods I can use. I am currently stuck at a position where I need to define the flow of the system.

In the gasifier, the bed is formed on the grate and when the particles are small enough, they fall down. The gas formed leaves from a gas outlet below the grate. There is a water seal at the bottom (the end of the gasifier is dipped in a bucket of water). This allows the ash to go in the water but prevents the gas from escaping from the bottom. Right now, I am really confused as to how I can setup the boundary condition that will allow only solid to flow through that and the gas only leaves from the other outlet. I have tried fixing the values in the zone and also by putting in a porous region with high resistance but both the methods are not working.

Is there any other way I can model this boundary condition? Please ask any clarification if you need. Thanks in advance :D