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-   -   The stream flow does not go thru outlet. (https://www.cfd-online.com/Forums/main/231616-stream-flow-does-not-go-thru-outlet.html)

Alfinmp November 12, 2020 02:00

The stream flow does not go thru outlet.
 
1 Attachment(s)
Hello there!
I was making 2 domains inside a fluid domain and defined one of it as inlet and the other as outlet. But once i tried to running it, the flows didnt go out thru outlet as i defined before.

I made 3 mm gap between drum and housing domain so the fluids could be able to moved into the drum and expectedly to go out to outlet.

But its just hit the drum and nothing happened, do you guys think i miss some boundaries or my geometry is not correct at all?

I attached a picture here.

AtoHM November 12, 2020 02:11

Normally, one fluid domain is defined with a region of faces as inlet and another region if faces for outlet. Or more regions if multiple in- or outlets are present. Multiple domains are possible, but do not seem to be required in your case. What software are you using? Have you done basic tutorials?
There is no image attached btw.

Alfinmp November 12, 2020 02:16

Quote:

Originally Posted by AtoHM (Post 787492)
Normally, one fluid domain is defined with a region of faces as inlet and another region if faces for outlet. Or more regions if multiple in- or outlets are present. Multiple domains are possible, but do not seem to be required in your case. What software are you using? Have you done basic tutorials?
There is no image attached btw.

I have done basic tutorials, i am using Ansys 16.0
http://prntscr.com/vh8njy You can check my result in that link.

AtoHM November 12, 2020 02:22

Upload images to the forum as attachment - people don't like following links with unknown targets.
"ANSYS" has 2 major CFD tools: CFX and Fluent.

Alfinmp November 12, 2020 02:44

1 Attachment(s)
Quote:

Originally Posted by AtoHM (Post 787494)
Upload images to the forum as attachment - people don't like following links with unknown targets.
"ANSYS" has 2 major CFD tools: CFX and Fluent.

Okay thank you for your suggest.
i am using Ansys Fluent for my simulation.
here my screenshot sir.

AtoHM November 12, 2020 02:58

From the image I can only guess you need to rethink what you need to model. It looks to me as if you have mixed up solids and fluid volumes in one model. You want to see what the flow does inside the volume given to it. You don't need to model solid walls as bodies. Solid walls are usually the boundary -> outer faces of your fluid domain. Create one body containing the fluid, create boundary for inlet and one for outlet, and everything should be fine.

Alfinmp November 12, 2020 03:09

so in your point is that i have to make inlet and outlet just in the outter boundary. so it is not possible to make an inlet inside the domain itself?

AtoHM November 12, 2020 03:29

It is possible and called a source term, but usually fluid is added through an inlet and thats where your model starts. It looks like you have some pipes where the fluid enters and they merge with the drum right? Then go, model the drum and add a part of each pipe and at the end of the pipes there will be your inlet.

Alfinmp November 12, 2020 03:51

2 Attachment(s)
Yes, but i assumed the pipe as pipe burner. The holes inside the pipe are inlet i expected that the flow would move and passed the drum and go inside the drum and go out to outlet. I defined the drum as wall and front drum as wall behind drum as interface thats all the boundary. I have attached two pictures as expected flow i wanted, that was from my past simulation. From that one theres no pipe inside it, but only the ground of the boundary ii defined as inlet.

AtoHM November 13, 2020 02:26

Honestly, it is hard for me to understand what you are doing, you are giving away information piece by piece. There is 10 posts here and now there is a second thread where you attached these images, which has a completely different main topic as far as I can see. May I suggest the following: create a new thread in the Fluent subforum, make a thorough post what you are trying to achieve, go through the boundary conditions you have set (make images where it is clearly visible where you set them in the gui) and what domains you have (I still doubt you need more than one).

Gerry Kan November 13, 2020 03:28

Dear Alfin:

I think streamlines are not cross-domain. That is, streamlines started from one fluid domain cannot continue on into another domain.

What I would suggest you to do is to reintroduce the streamlines again in your drum and see if you have more success. I doubt people would notice the difference, given that streamlines has a tendency of starting and stopping in places you don't expect.

Gerry.

Alfinmp November 13, 2020 07:29

Quote:

Originally Posted by Gerry Kan (Post 787621)
Dear Alfin:

I think streamlines are not cross-domain. That is, streamlines started from one fluid domain cannot continue in a second domain.

What I would suggest you to do is to reintroduce the streamlines again in your drum and see if you have more successes. I doubt people would notice the difference, given that streamlines has a tendency of starting and stopping.

Gerry.

Yah that is Mr. Gerry, how to reintroduce it by the way? I need the streamlines to cross the drum domain as you said. How to re-continue it? I am stuck on it.

Gerry Kan November 13, 2020 12:21

You are not making direct continuations of the streamlines from the inlets to the drum; you are generating new streamlines from the drum inlet to make it look like they are continuation from the domain upstream.

I don't remember how this is done in CFDPost. In other softwares you introduce streamlines either in a surface or s point in the domain volume. Do you have an interface surface between the pirts and the drum from which the streamlines can be seeded?

Gerry.

Alfinmp November 13, 2020 12:49

Yes i do have interface from inlet pipe to the domain, but theres no interface for drum cause i want to define it as wall. Or do you think i have to define the interface for drum too?

Gerry Kan November 13, 2020 18:41

Since you defined two flow domains you should have an interface between them if they are adjacent. If you cannot choose the interface in question you should be able to define your own streaming seeding regions in the drum on your own. You can do this in other post-processing softwares, so I would think you could also do this in CFDPost.

Alfinmp November 14, 2020 08:55

Quote:

Originally Posted by Gerry Kan (Post 787710)
Since you defined two flow domains you should have an interface between them if they are adjacent. If you cannot choose the interface in question you should be able to define your own streaming seeding regions in the drum on your own. You can do this in other post-processing softwares, so I would think you could also do this in CFDPost.

i tried it already Mr. Gerry but it is not as i expected, the streamline just neglecting the drum as it was not there its just flow and still not go out to the outlet.

Gerry Kan November 14, 2020 14:45

At the risk of pointing you to a direction that seems obvious, have you checked the velocity magnitude in the drum to make sure there is flow from the pipes into the drum and into the outlet?

Alfinmp November 15, 2020 16:31

Quote:

Originally Posted by Gerry Kan (Post 787772)
At the risk of pointing you to a direction that seems obvious, have you checked the velocity magnitide in the drum to make sure there is flow from the pipes into the drum and in the outlet?

When i checked the velocity magnitude in the drum nothing happened on the surface and also on the contour, but when i tried to make streamline all over the domain, the streamline appeared just exaclty from inlet to outlet. But still i think the contacts region surrounding the drum just blocked it up. I am figuring it out now how to solve that one. Thank you for your help Mr. Gerry.

Alfinmp November 26, 2020 02:25

Quote:

Originally Posted by Gerry Kan (Post 787772)
At the risk of pointing you to a direction that seems obvious, have you checked the velocity magnitude in the drum to make sure there is flow from the pipes into the drum and into the outlet?

Yup theres streamline there, but why fluent cut the continuity by the way?


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