| stonepreston |
October 29, 2017 14:54 |
Two Phase Flow In Vertical Pipe
I am trying to model a two phase flow in a vertical pipe using a boiling model.
I used the 2nd part of this tutorial to guide my process.
The problem I am trying to model is given below:
A vertical steel tube carries water at a pressure of 10 bars. Saturated liquid water is pumped into the D = 0.1 m diameter tube at its bottom end (x = 0) with a mean velocity of um= 0.05 m/s. The tube is exposed to combusting pulverized coal, providing a uniform heat flux of q” = 100,000 W/m2. The total length of the pipe is 30 meters.
A small piece of my mesh is shown here:
https://imgur.com/a/fT73G
I followed the tutorial to setup the eulerian boilding mode. I copied the liquid water and water vapor materials from the fluent database, setup the two phases, and specified the phase interactions. I made sure to change the saturation temperature in the boiling mass transfer mechanism to the saturation temperature at 10 bar.
I specified the inlet velocity as .05 m/s for the liquid phase, and 0 for the vapor phase (since its a saturated liquid at the inlet). I also specified a gage pressure of 1000000 at the inlet for the mixture and 0 pressure at the outlet for the mixture.
When I try to initialize, I get the following error:
Code:
Initialize using the hybrid initialization method.
Checking case topology...
-This case has both inlets & outlets
-Pressure information is not available at the boundaries.
Case will be initialized with constant pressure
iter scalar-0
1 0.000000e+00
2 0.000000e+00
3 0.000000e+00
4 0.000000e+00
5 0.000000e+00
6 0.000000e+00
7 0.000000e+00
8 0.000000e+00
9 0.000000e+00
10 0.000000e+00
hybrid initialization is done.
# Divergence detected in AMG for ads-0: protective actions enabled!
# Divergence detected in AMG for ads-0, temporarily solve with BCGSTAB!
Divergence detected in AMG solver: ads-0# Divergence detected in AMG for ads-0: protective actions enabled!
# Divergence detected in AMG for ads-0, temporarily solve with BCGSTAB!
Divergence detected in AMG solver: ads-0# Divergence detected in AMG for ads-0: protective actions enabled!
# Divergence detected in AMG for ads-0, temporarily solve with BCGSTAB!
Divergence detected in AMG solver: ads-0# Divergence detected in AMG for ads-0: protective actions enabled!
# Divergence detected in AMG for ads-0, temporarily solve with BCGSTAB!
Divergence detected in AMG solver: ads-0# Divergence detected in AMG for ads-0: protective actions enabled!
# Divergence detected in AMG for ads-0, temporarily solve with BCGSTAB!
Divergence detected in AMG solver: ads-0# Divergence detected in AMG for ads-0: protective actions enabled!
# Divergence detected in AMG for ads-0, temporarily solve with BCGSTAB!
Divergence detected in AMG solver: ads-0# Divergence detected in AMG for ads-0: protective actions enabled!
# Divergence detected in AMG for ads-0, temporarily solve with BCGSTAB!
Divergence detected in AMG solver: ads-0# Divergence detected in AMG for ads-0: protective actions enabled!
# Divergence detected in AMG for ads-0, temporarily solve with BCGSTAB!
Divergence detected in AMG solver: ads-0# Divergence detected in AMG for ads-0: protective actions enabled!
# Divergence detected in AMG for ads-0, temporarily solve with BCGSTAB!
Divergence detected in AMG solver: ads-0# Divergence detected in AMG for ads-0: protective actions enabled!
# Divergence detected in AMG for ads-0, temporarily solve with BCGSTAB!
Divergence detected in AMG solver: ads-0
Error at host: floating point exception
Error at Node 0: floating point exception
Error: floating point exception
Error Object: #f
How can I resolve this error? Is the problem with my mesh?
Here is my mesh check:
Code:
Domain Extents:
x-coordinate: min (m) = 2.078713e-01, max (m) = 2.578713e-01
y-coordinate: min (m) = 0.000000e+00, max (m) = 3.000000e+01
Volume statistics:
minimum volume (m3): 1.320992e-07
maximum volume (m3): 7.924628e-03
total volume (m3): 1.413717e+02
minimum 2d volume (m3): 4.204847e-06
maximum 2d volume (m3): 4.204847e-05
Face area statistics:
minimum face area (m2): 4.204847e-04
maximum face area (m2): 1.000000e-02
Checking mesh............................
Done.
and my mesh quality:
Code:
Mesh Quality:
Minimum Orthogonal Quality = 1.00000e+00
(To improve Orthogonal quality , use "Inverse Orthogonal Quality" in Fluent Meshing,
where Inverse Orthogonal Quality = 1 - Orthogonal Quality)
Maximum Aspect Ratio = 2.38031e+01
|
