November 16, 2022 at 12:43 pmabhnv_01Subscriber
I am working with 2-D transient simulation with compressible flow, gravity assisted.
I am using VOF- multiphase model and evaporation condensation model as the phase change model, with saturation temperature as a function of saturation pressure.
Liquid is primary phase and Vapor is secondary phase.
liquid properties - piece-wise polynomial function of temperature
vapor density - Ideal gas
vapor viscosity and thermal conductivity - piece-wise poly function of temperature.
Operating pressure - (Floating) 0 Pa, gauge pressure - 76043 Pa
Operating density - 0 kg/m3
Initial temp - 75K
CONVERGANCE criteria -
(continuity - 1e-05), (velocity - 1e-04) and (energy - 1e-06)
Pressure-velocity coupling - SIMPLE
Gradient - Least squares cell based
Pressure - PRESTO
Density - second order upwind
Momentum - Quick
Volume fraction - Conpressive
Energy - first order upwind
All the URFs are default.
The temperature of the evaporator section is increasing. I do not understand why..
Any help will be highly appreciated.
November 16, 2022 at 1:47 pmRobAnsys Employee
What are the boundary conditions?
November 16, 2022 at 1:58 pm
November 16, 2022 at 2:24 pmRobAnsys Employee
Evaporator section will increase in temperature because the wall MUST push in the defined heat flux. So, that wall will heat up to infinity if you don't extract sufficient energy from the condensor section.
November 16, 2022 at 3:44 pmabhnv_01Subscriber
Rightly said Rob.
Thanks for the reply.
The boundary conditions are set according to experimental values.
Regarding the sufficient energy generated on the condensor section, I have two queries as following:
Say, if I am not being able to get sufficient cold from the condenser section, will it be the right way to decrease the condensor temperature to get enough cold?
Or is there any way to check whether enough cold is generated on the condensor side or not?
November 16, 2022 at 3:46 pmRobAnsys Employee
That depends on what you want to adjust: I can only advise on what the solver is doing, not what boundary values you ought to pick.
I also assume that the mesh is sufficiently well refined to pick up the wall & free surface boiling & flow.
November 24, 2022 at 6:59 amabhnv_01Subscriber
Yes, my mesh is well refined.
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