Learning Forum

[Lakshay]

ACTUALLY I AM WORKING ON A PHASE CHANGE SIMULATION OF FOG TO LIQUID WATER. THE STRUCTURE IS LIKE A TETRAHEDRON, OPEN AT ONE FRONT FACE. THE FOG WILL ENTER INTO THE TETRAHEDRON, AND WILL PASS THROUGH THE SMALL CAVITIES PRESENT IN THE BOTTOM PART OF TETRAHEDRON WALLS. THE AIM IS TO CAPTURE THE MOISTURE IN THIS STRUCTURE. I AM HAVING DOUBTS ABOUT DEFINING THE BOUNDARY CONDITIONS AND INLET AND OUTLET IN THE ANSYS SOFTWARE.nn

[DrAmine]

Which Ansys software are you using? Can you please avoid writing with CAPITAL letters?n

[Lakshay]

I am using Ansys 19 R1.nn

[Lakshay]

Actually I made the structure and after doing the enclosure thing, I named the front of structure as inlet, rear as outlet and other 4 walls as walls. In the Fluent section - I kept Energy (ON), Multiphase - (Volume of Fluid) and viscosity (k-epsilon with enhanced wall treatment). I took two materials which are water Vapor and Water Liquid. The primary phase is water Vapor changing to water Liquid. In the Boundary conditions, I am giving velocity input of 60kmph at the inlet and then when I am trying to initialize, I am getting this error. I don't know where I am doing wrong.nn

[YasserSelima]

Your interior is defined as solidn

[Lakshay]

There is no option to change it to Fluid. n

[Rob]

Go to Cell Zones, is the cell zone a fluid or solid? Please plot a mesh plane through the middle of the model to help understand what is fluid and what isn't included in the model. nI also recommend updating to 2021R1 to take advantage of the wall film and VOF interaction. Trying this in VOF only isn't going to be easy. n

[DrAmine]

I recommend to do a couple of tutorials before you get started with very challenging application. You need to get familiar first with the software.nnWe can handle fog build-up with a couple of approaches starting from simple to high end.n

[Lakshay]

Actually I also tried going by a different approach of including the fog domain into the cad and them applying material to it, but still no success. In the image below, the grey part is metallic structure and the red triangles and green triangles and completely filled in the structure (air front and air rear respectively). I selected the front surface of these red and green air parts as inlet and the rear smaller visible part as outlet, but in the fluent there is no OUTLET showing in boundary conditions. You can see the OUTLET that I have selected in the below image.nnn

[Rob]

Can you post an image of a mesh cut plane in Meshing so we can see where the mesh is? n

[Lakshay]

Sir is this what you are asking for?nn

[Rob]

OK, part of the problem is there is no outside in your domain. You have the metal part and cavity only. The mesh is also far too coarse to resolve the flow field, and I don't think the volumes are connected so there are no faces to assign as the outlet on the cavity. nGo through the tutorials that come with the software, as that will help get you going with the basics. From there you'll see what you need to do for the above case and will know what questions to ask. n