Discussion Forum

I've been trying to model a microchannel evaporator to match up real world test data for some time. My school recently purchased the heat transfer and CFD modules, as well as previously purchasing the microfluidics module, so I believe I have all of the necessary input equations to model my situation. I've been struggling with ensuring that I'm defining everything properly in the physics and boundary conditions. The evaporator is using water as the input fluid medium, with pure saturated steam at the outlet. It is a silicon microchannel that is insulated by pyrex (borosilicate) on the top and bottom. There is a constant surface temperature on the exit face side of the evaporator channel (at 120 DegC). I've assumed everything else to be at ambient of 20 DegC. Any help to get the physics and boundary conditions would be greatly appreciated.

Note: I'm new to Comsol, but have used several other CFD suites in the past for commercial applications. I'm sure that most of my issues are not fully understanding this software. I've attached a copy of the basic model I'm working with along with the physics and mesh I set up.

The things I'd like to understand are:
1. How to define the Initial Interface Properly
2. How to define which regions (or surfaces) are for water and which are for steam
3. How to ensure the heat source (1.8W or 120 DegC wall temp) are defined
4. How to define the study properly (assuming I should use transient solution here)
5. If I need to define a larger volume in geometry to be ambient room (to allow for convection).