Learning Forum

[nagasudhan]

When I tried creating solidification/melting model for phase change materials(PCMs) , I ended up with following error message 

Boundary conditions used:

1. Inlet - Mass-flow inlet - 3kg/s, Temp - 363K

2. outlet - pressure outlet - 101325 pa (gauge pressure)

Material property:

1. PCM solidus temp, liquidus temp : 494 K, 511K

2. Water: Fluent default

 

Error message:

ter continuity x-velocity y-velocity z-velocity energy time/iter

32 1.7098e+09 4.6928e-01 1.8290e-01 3.1616e-01 1.6942e-04 0:00:12 1

Stabilizing temperature to enhance linear solver robustness.

Stabilizing temperature using GMRES to enhance linear solver robustness.

temperature limited to 1.000000e+00 in 1013 cells on zone 7 in domain 1

temperature limited to 5.000000e+03 in 5428 cells on zone 7 in domain 1

temperature limited to 1.000000e+00 in 23995 cells on zone 6 in domain 1

 

temperature limited to 5.000000e+03 in 38774 cells on zone 6 in domain 1

Reversed flow on 67 faces (67.6% area) of pressure-outlet 10.

(update-animation-object "animation-1")()

Flow time = 33s, time step = 33

167 more time steps

Updating solution at time level N...

done.

iter continuity x-velocity y-velocity z-velocity energy time/iter

 

33 2.4241e+11 4.9479e-01 1.9709e-01 2.6575e-01 1.5073e-01 0:142 1

 

Stabilizing x-momentum to enhance linear solver robustness.

Stabilizing temperature to enhance linear solver robustness.

Stabilizing temperature using GMRES to enhance linear solver robustness.

Divergence detected in AMG solver: temperature

Reversed flow on 52 faces (53.6% area) of pressure-outlet 10.

Divergence detected in AMG solver: temperature

Error at host: floating point exception

Error at Node 0: floating point exception

Error at Node 1: floating point exception

Error at Node 2: floating point exception

Error at Node 3: floating point exception

Compute processes interrupted. Processing can be resumed.

Error: floating point exception

Calculation complete.

 

Attached images showing Liquid - fraction of PCM balls

 

[nagasudhan]

[RK]

Hello,

What is the courant number you have specified? Are you using "Higher Order Term Relaxation" option? 

Regards,

Rahul 

[nagasudhan]

I didn't specify any courant number, it should be default and relaxations factors are assigned by fluent, I have attached a screenshot below.

Relaxation method - Gauss seidel

 

[Rob]

To rephrase Rahul's question. For the given time step, what is the Courant Number? 

[nagasudhan]

Courant number is set default. It is 500 for this case

Solver setup is coupled.