Modeling two-phase (blood and oxygen) slug flow in a y-junction

saynovich · May 13, 2014, 10:42

Hi everyone,

I recently started to learn how to use Fluent, so I am in the beginning of the learning curve.

I want to model a two-phase slug flow of blood and oxygen bubbles in a y-junction (as represented in the picture attached).

I imported a 3D part from SolidWorks, and the y-junction is one of the several tubes in the model. My doubts are:

Do I need to model the junction again in the Fluent DesignModeler? After importing the model in Ansys, it is not possible to select all the points, edges and surfaces, and it is hard to define the boundary conditions this way, so I decided to model only one of the y-junctions.
What type of mesh should I use? As I am not familiar with the program, I dont know what mesh to use. Also, I think I cannot analyse it with a 2D mesh. Due to the y-junction, the problem is not axysimmetric, so I need a 3D mesh, right?

two-phase-flow-y-junction.jpg

Thank you guys for your time and help.

Regards,

laraib · May 13, 2014, 13:01

i have carried out similar simulations. you dont need to make a new geometry in ICEM . just import the one from solid work and clean it and define input and output surfaces.
u can use unstructured mesh tetrahedron . that will give you good results

saynovich · May 13, 2014, 16:47

Quote:

Originally Posted by laraib

i have carried out similar simulations. you dont need to make a new geometry in ICEM . just import the one from solid work and clean it and define input and output surfaces.
u can use unstructured mesh tetrahedron . that will give you good results

Hi laraib, thank you for the answer.

What do you mean by clean it? Supress all the faces, but the ones I want to model?

Did you model two-phase flow? I am currently using the VOF model ( I think it is the one more appropriate for two-phase slug flow). Which one do you usually use?

laraib · May 16, 2014, 02:14

i am rather curious that why r u using VOF model?? its used for two phase fluid flow. and flow in arteries is not two phase as oxygen is absorbed by the RBCs.
and if u still want to then clean up the geometry by deleting extra surfaces.
like in ur model there is thickness between outer and inner layer which may not be required.
produce a 3d mesh with either tetrahedral or hexagonal elements. u can have a 2d mesh too.

May 13, 2014, 10:42	Modeling two-phase (blood and oxygen) slug flow in a y-junction	#1
saynovich New Member Pedro Saynovich Join Date: May 2014 Posts: 3 Rep Power: 12	Hi everyone, I recently started to learn how to use Fluent, so I am in the beginning of the learning curve. I want to model a two-phase slug flow of blood and oxygen bubbles in a y-junction (as represented in the picture attached). I imported a 3D part from SolidWorks, and the y-junction is one of the several tubes in the model. My doubts are: Do I need to model the junction again in the Fluent DesignModeler? After importing the model in Ansys, it is not possible to select all the points, edges and surfaces, and it is hard to define the boundary conditions this way, so I decided to model only one of the y-junctions. What type of mesh should I use? As I am not familiar with the program, I dont know what mesh to use. Also, I think I cannot analyse it with a 2D mesh. Due to the y-junction, the problem is not axysimmetric, so I need a 3D mesh, right? two-phase-flow-y-junction.jpg Thank you guys for your time and help. Regards,

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May 13, 2014, 13:01		#2
laraib New Member laraib syed Join Date: Apr 2014 Posts: 13 Rep Power: 12	i have carried out similar simulations. you dont need to make a new geometry in ICEM . just import the one from solid work and clean it and define input and output surfaces. u can use unstructured mesh tetrahedron . that will give you good results

May 16, 2014, 02:14		#4
laraib New Member laraib syed Join Date: Apr 2014 Posts: 13 Rep Power: 12	i am rather curious that why r u using VOF model?? its used for two phase fluid flow. and flow in arteries is not two phase as oxygen is absorbed by the RBCs. and if u still want to then clean up the geometry by deleting extra surfaces. like in ur model there is thickness between outer and inner layer which may not be required. produce a 3d mesh with either tetrahedral or hexagonal elements. u can have a 2d mesh too.