[hubert79]

hi,
I feel very confused when i tried to cite a research paper which focus the CFD simulation of vapour condensation in presence of non-condensable gas(ref.1).

The situation concerning my question in the paper as following:

The gas mixture(water vapour + air, modeling as multi-species material) flows from the top into a vertical cylindrical condenser tube with a annular cooling jacket into which the coolant water liquid flows from bottom ,and the film-wise condensation of the gas mixture takes place on the wall of the condenser tube.

However,in the proceeding simulation of heat transfer, the author of the paper announces that : the FLUENT support only a single mixture material for species calculations in the entire domain on heat transfer application involves two fluid regions separated by a solid wall(ref.2), so ,because of this, the two flows in the present situation including the air-vapor mixture and the cooling water cannot be simulated simultaneously using FLUENT since the flow in one channel is a mixture of air and water vapor, and in the other channel the flow is water liquid. FLUENT can model
two flows separated by a solid wall only if one flow is water, say, and the other is air.

I have two questions in connection with the author's above view:
1, the present situation includes just one single mixture material(water vapour + air),which is supported by FLUENT, so, the simultaneous simulations in the condenser and coolant channel should been carried out with no problems.

2,if the FLUENT's and the author's statements are correct, why? what is the reason behind?

thanks for helps and discusses.

references:
1, Section "Step 2"
Saraireh, Mohammad, and Graham Thorpe. "Simulation of heat and mass transfer involving vapor condensation in the presence of non-condensable gases in plane channels." ASME/JSME 2011 8th Thermal Engineering Joint Conference. American Society of Mechanical Engineers, 2011.

2,Section "14.2.1.2. Modeling Heat Transfer in Two Separated Fluid Regions"
ANSYS FLUENT User's Guide,Release 14.0, November 2011