Water vapour condensation in CFX-5.7.1
 

Hi

I'm trying to simulate water vapour condensation on surface. I've modified boiling_water.ccl in /etc/model-templates. But condensation seems not start. I've tried various Nu, boundary conditions (wall temperature) etc. with no success. Boiling itself is quite good calculated. Has anybody some experience on this? I am using CFX-5.7.1. Any suggestion will be appreciated.

Below is an example of the model.

Best regards.

NuL = 6

NuV = 2000

Pref = 1.014 [bar]

Tsat = 100. [C]

Tdown = Tsat-20 [C]

DOMAIN: boiling device

Coord Frame = Coord 0

Domain Type = Fluid

Fluids List = Water at 100 C,Water Vapour at 100 C

Location = Assembly

BOUNDARY: OUT

Boundary Type = OUTLET

Location = OUT

BOUNDARY CONDITIONS:

FLOW REGIME:

Option = Subsonic

END

MASS AND MOMENTUM:

Option = Average Static Pressure

Relative Pressure = Pref

END

PRESSURE AVERAGING:

Option = Average Over Whole Outlet

END END END

BOUNDARY: SYM

Boundary Type = SYMMETRY

Location = SYM1,SYM2

END

BOUNDARY: UP

Boundary Type = WALL

Location = WALLU

BOUNDARY CONDITIONS:

HEAT TRANSFER:

Option = Fluid Dependent

END END

FLUID: Water Vapour at 100 C

BOUNDARY CONDITIONS:

HEAT TRANSFER:

Option = Adiabatic

END

WALL INFLUENCE ON FLOW:

Option = No Slip

END END END

FLUID: Water at 100 C

BOUNDARY CONDITIONS:

HEAT TRANSFER:

Option = Adiabatic

END

WALL INFLUENCE ON FLOW:

Option = No Slip

END END END

WALL CONTACT MODEL:

Option = Use Volume Fraction

END END

DOMAIN MODELS:

BUOYANCY MODEL:

Option = Non Buoyant

END

DOMAIN MOTION:

Option = Stationary

END

REFERENCE PRESSURE:

Reference Pressure = Pref

END END

FLUID MODELS:

COMBUSTION MODEL:

Option = None

END

HEAT TRANSFER MODEL:

Homogeneous Model = False

Option = Fluid Dependent

END

THERMAL RADIATION MODEL:

Option = None

END

TURBULENCE MODEL:

Homogeneous Model = False

Option = Laminar

END END

FLUID PAIR: Water Vapour at 100 C | Water at 100 C

INTERPHASE HEAT TRANSFER:

Option = Two Resistance

FLUID1 INTERPHASE HEAT TRANSFER:

Fluid1 Nusselt Number = NuV

Option = Nusselt Number

END

FLUID2 INTERPHASE HEAT TRANSFER:

Fluid2 Nusselt Number = NuL

Option = Nusselt Number

END END

INTERPHASE TRANSFER MODEL:

Option = Particle Model

END

MASS TRANSFER:

Option = Phase Change

PHASE CHANGE MODEL:

Option = Thermal Phase Change

Saturation Temperature = Tsat

END END

MOMENTUM TRANSFER:

DRAG FORCE:

Option = Schiller Naumann

END

LIFT FORCE:

Option = None

END

VIRTUAL MASS FORCE:

Option = None

END

WALL LUBRICATION FORCE:

Option = None

END END

SURFACE TENSION MODEL:

Option = None

END END

FLUID: Water Vapour at 100 C

FLUID MODELS:

HEAT TRANSFER MODEL:

Option = Thermal Energy

END

MORPHOLOGY:

Option = Continuous Fluid

END END END

FLUID: Water at 100 C

FLUID MODELS:

HEAT TRANSFER MODEL:

Option = Thermal Energy

END

MORPHOLOGY:

Mean Diameter = 1 [mm]

Option = Dispersed Fluid

END END END

MULTIPHASE MODELS:

Homogeneous Model = Off

FREE SURFACE MODEL:

Option = Standard

END END

BOUNDARY: DOWN

Boundary Type = WALL

Location = WALLD

BOUNDARY CONDITIONS:

HEAT TRANSFER:

Option = Fluid Dependent

END END

FLUID: Water Vapour at 100 C

BOUNDARY CONDITIONS:

HEAT TRANSFER:

Fixed Temperature = Tdown

Option = Fixed Temperature

END

WALL INFLUENCE ON FLOW:

Option = No Slip

END END END

FLUID: Water at 100 C

BOUNDARY CONDITIONS:

HEAT TRANSFER:

Fixed Temperature = Tdown

Option = Fixed Temperature

END

WALL INFLUENCE ON FLOW:

Option = No Slip

END END END

WALL CONTACT MODEL:

Option = Use Volume Fraction

END END

BOUNDARY: IN

Boundary Type = INLET

Location = IN

BOUNDARY CONDITIONS:

FLOW DIRECTION:

Option = Normal to Boundary Condition

END

FLOW REGIME:

Option = Subsonic

END

HEAT TRANSFER:

Option = Fluid Dependent

END

MASS AND MOMENTUM:

Option = Total Pressure

Relative Pressure = 1.001*Pref

END END

FLUID: Water Vapour at 100 C

BOUNDARY CONDITIONS:

HEAT TRANSFER:

Option = Static Temperature

Static Temperature = Tsat

END

VOLUME FRACTION:

Option = Value

Volume Fraction = 1

END END END

FLUID: Water at 100 C

BOUNDARY CONDITIONS:

HEAT TRANSFER:

Option = Static Temperature

Static Temperature = Tsat

END

VOLUME FRACTION:

Option = Value

Volume Fraction = 0

END END END END ENDEND

Re: Water vapour condensation in CFX-5.7.1
 

hello I am interesting in the condensation in the presence of non condensable gases...I want to use CFX in the modeling of the condenser, any help or cooperation is welcome. I am not a professional in the field of CFX or Ansys. thanks