multiphas flow in double pipes
 

Hi
I am trying to model a two phase flow which is consist of vertical double pipe tube. Very hot gas is flowing through the inner pipe and water is the fluid of outer pipe. The water will be vaporized by the heat of the gas and steam bubbles will be appeared. Gas does not have any phase change ; just becomes cooler. I use the mixture model for two phase flow consist of water and steam. Am i right? If not which model is suitable for this case?
The next question is that when i define the gas, in Boundary Condition , fluent activates the 3phases: mixture, phase1 and phase2‎ for gas, while the gas doesn't have any phase change.How can i fix this?
Thanks in advance.

Hi kh91,

Could you solve your problem??

I am going to perform the same simulation. I am working on the mesh right now, but I will be facing this later

Thanks in advance...