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-   -   Condensation of refrigerant inside the circular tube (http://www.cfd-online.com/Forums/fluent/87751-condensation-refrigerant-inside-circular-tube.html)

 vishalpatil April 28, 2011 07:33

Condensation of refrigerant inside the circular tube

I am working on simulation of condensation of refrigerant inside the circular tube.
In this problem i have used Eulerian multiphase model ..It s asking bubble diameter for secondary phase(refrigerant in liquid phase)....how do i calculate it....Another problem is operating pressure .....My inlet pressure is 15.5 bar and outlet is 15.3....then what would be the pressure outlet condition and....... operating pressure.

 kurne April 30, 2011 07:19

Dear Vishal

 vishalpatil May 2, 2011 04:31

Quote:
 Originally Posted by kurne (Post 305695) Dear Vishal Will u please elaborate your problem in detail.
Hi ,
Dear sir,
I am working on condensation of refrigerant inside the smooth long circular tube. I am using fluent for the same. My problem setup is like this
Models -
1.Multiphase-Eulerian
2.Energy
3.K-e,realizable,std wall,mixture
Materials-
1.R404a-vapor(primary phase)-Its properties
2.R404a-liquid-(secondary phase)-Its properties
Phases
1.Primary-R404a-vapor
2.Secondary-R404a-liquid
-Bubble diameter1e-05(assumed-do not know)
phase interaction
Drag-Symmetric
Heat-ranz marshall
Mass transfer-r404a vapor to r404a-liquid through evaporation condensation at constant saturation temp.
surface tension constant
Boundary conditions
Inlet -Velocity inlet for mixture and each phase(Turbulence intensity 4% & Hydraulic dia 0.00814mm for each phase)
outlet-pressure outlet-0 gauge pressure
tube wall at constant wall temp.much more below saturation temp.
operating pressure is atm.(:confused:my condensing pressure is 15 bar gauge..... what to be used operating pressure and pressure at the outlet)
Solution method
phase coupled simple
Volume fraction-modified HRIC, all others Quick
initialization from all zones.
I have not included Enthalpy
My solution giving no condensation at any point in the tube........not a single sign.
am i going in right way