How to create 2 different fluid regions
 

I have 3 different surfaces Solid, Steam and Gas under different part names in ICEM. When I import the mesh into Fluent, under Materials I am getting only air under Fluid, whereas I want two materials under Fluid, one for Gas and another for Steam. What should I do so that I have three separate materials? Can it be done in ICEM or is it something that has to be done in Fluent? I am using version 14.

three material means three bodies. you have to create three bodies. you will find that tool the geometry tab. all you need to do is select two point (extremities )and the body will be created in the centroid of those two point. for example if you want a body for the solid region (tube) select one point in the inner surface another one in the outer surface.

Actually mine is 2D. What I did was simple, I meshed it, imported in Fluent and in Materials, under fluid I click create/edit, change the various properties and click change/create. Here it will ask "would like to overwrite?" Just hit no and it will create another material under fluid. Then in Cell Zone Conditions I select the appropriate zone and hit Edit and change the material name.
Is this right?
I will also explain the problem and doubts I have:
1. The gas enters from the edge marked in pic with temp 500K and pressure of 100Pa. BC Type Pressure Inlet. There are 2 Gauge total pressure and Supersonic/Initial Gauge Pressure. Which one should I use?
2. The steam is at a temperature of 200K. BC Type Wall
3. I make the left and right edges periodic.
4. I do not know the exit conditions.
5. My objective is to find the solid wall temperature.

I created 3 materials in fluent because there are 3 zones - gas, steam and solid with different properties. Do I need 3 materials or just 2 is enough - steam and solid and give just temp. and pressure for flue gas?
The exit I tried to make Type as Outflow but I get this "Warning: Both outflow and pressure boundaries are present in the domain. This is an incompatibility and solution cannot proceed until this is fixed." So what type should I make exit as?

yes

this is more about how to set boundaries condition, you will get more help if you address your problem in the fluent section. a lots of people deal with thermal analysis there.
- it's better to try mass flow inlet instead of pressure inlet.
- you don't have to know the exit condition, leave it the default pressure outlet
- you don't need three materials, you can emit the solid material, in fact, when assigning wall for the tubes, you can specify the thickness and the material , fluent will take care to simulate that real thickness you have while calculating.

this is all i know about it. hope it can help. don't forget to transfer this thread in the fluent section

Thank you very much diamondx. How do I transfer this thread? Should I create a new Thread in the Fluent section?

yes just start a new thread there !!