CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > ANSYS Meshing & Geometry

[ANSYS Meshing] Simple heat exchanger meshing

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   October 26, 2021, 03:56
Default Simple heat exchanger meshing
  #1
New Member
 
Join Date: Oct 2021
Posts: 3
Rep Power: 2
Scaty is on a distinguished road
Hi everybody,

I tried to set up a fairly simple case in ANSYS Workbench with the solver Fluent.
Later on I will solve a heat exchanger, but as this is quite perfomance-demanding I carry out the meshing-study with a simplified model to find out which meshing I should use in the later full model to get a reliable result.

My model is a 2D rectangular (0.04 m wide and 1 m long) with a velocity inlet on the left side and a no-pressure outlet on the right. The long walls are my boundaries and both are set to no-slip and a fixed temperature of 20 C. My inlet temperature is 80 C and the velocity is high enough to ensure a turbulent flow (Reynolds number above 10000, I use the k-epsilon turbulence model).

Now about my actual question. Every time I change the meshing before running the solver, my results change significantly. At first when the mesh is rather coarse that is plausible as such a coarse mesh is presumably not able to solve the boundary layers on both sides. But even if I refine my mesh or add inflation layers at the edges, or even if I generally increase the number of cells, my results keep changing (sometimes with fine meshes they even diverge?). Usually I expect only slight alterations in the solution when I reached the point on which the mesh is good enough, but that never happens.

Logically I am mostly interested in the temperature profile and the average outlet temperature, but the other values like pressure and velocity keep changing as well.

Is there anything I am doing wrong, any ideas how I can resolve that issue?
I am happy about help, it is quite frustrating to spend hours and hours without any progress .
Scaty is offline   Reply With Quote

Old   October 27, 2021, 04:21
Default
  #2
Member
 
Chrowale
Join Date: Sep 2021
Location: Bandung, Indonesia
Posts: 40
Rep Power: 2
mluckyw is on a distinguished road
What Mesh shape do you use? I think for your case with a rectangular geometry would have more benefit by using a structured hexahedral mesh or in case of 2d QUAD surface mesh. How about the mesh quality? is it acceptable?
Have you tried by using another turbulence model such as SST and keeping the Y+ value to an appropriate value for each turbulence model?
mluckyw is offline   Reply With Quote

Reply

Tags
ansys, convergence, heat exchanger, meshing, workbench

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
[Gmsh] gmshToFoam generates patches with 0 faces and 0 points Simurgh OpenFOAM Meshing & Mesh Conversion 3 October 26, 2021 08:27
Apply heat sink/mimic heat exchanger in closed loop with buoyantBoussinesqPimpleFoam alex1001 OpenFOAM Running, Solving & CFD 0 October 28, 2019 13:38
[snappyHexMesh] meshing the geometry of an heat exchanger RobSie OpenFOAM Meshing & Mesh Conversion 0 November 30, 2016 10:22
[Gmsh] Vertex numbering is dense KateEisenhower OpenFOAM Meshing & Mesh Conversion 7 August 3, 2015 10:49
Convective Heat Transfer - Heat Exchanger Mark CFX 6 November 15, 2004 15:55


All times are GMT -4. The time now is 05:04.