Help! How to set boundary conditions of this model???

kylin1282869061 · December 23, 2013, 07:38

hello,everyone. I have a problem about boundary conditions.
here is the picture.

requirements:
The first condition: the boundary conditon of pipe face 1 is "exhaust", the air could flow into pipe through pipe face 2, so how to set the boundary conditions of roadway face 1 and roadway face 2.

The second condition: the boundary conditon of pipe face 1 is "pressure-inlet", the air could flow into roadway through pipe face 1, so how to set the boundary conditions of roadway face 1 and roadway face 2.

lovecraft22 · December 23, 2013, 13:49

What is roadway #? Are you trying to simply simulate an exhaust within a domain?

kylin1282869061 · December 23, 2013, 21:03

thank you,lovecraft.
the model is that a pipe is in another volume/domain(roadway),so there are two pairs of faces,namely 4 faces, they are pipe face 1 and roadway face 1, pipe face 2 and roadway face 2.
now, if the boundary conditon of pipe face 1 is "exhasut",how to set the boundary conditon of roadway face 1 to let the air flow into the roadway???
hope for your reply.

kylin1282869061 · December 23, 2013, 21:06

Quote:

Originally Posted by lovecraft22

What is roadway #? Are you trying to simply simulate an exhaust within a domain?

thank you,lovecraft.
the model is that a pipe is in another volume/domain(roadway),so there are two pairs of faces,namely 4 faces, they are pipe face 1 and roadway face 1, pipe face 2 and roadway face 2.
now, if the boundary conditon of pipe face 1 is "exhasut",how to set the boundary conditon of roadway face 1 to let the air flow into the roadway???
hope for your reply.

lovecraft22 · December 24, 2013, 11:49

Not sure I understand… you want air to be subtracted from the roadway and air to be added to the pipe but the air that goes out of the roadway is not the same air that enters the pipe, is that correct?

kylin1282869061 · December 25, 2013, 09:02

Quote:

Originally Posted by lovecraft22

Not sure I understand… you want air to be subtracted from the roadway and air to be added to the pipe but the air that goes out of the roadway is not the same air that enters the pipe, is that correct?

air is in the roadway, I want the air to be subtracted into the pipe from pipe face 2 and flow out of pipe from pipe face 1.
so I could set the boundary condition of pipe face 1 to be "exhuast fan" to offer "suction power" to subtract the air around pipe face 2.
but as the adjacent face, how to set the boundary condition of roadway face 1??
hope you could understand.

lovecraft22 · December 26, 2013, 12:48

What is it like in the real case? Is there a fan there?

kylin1282869061 · December 27, 2013, 22:46

yes, there is a fan at the end of pipe face 1 and I just set the boundary condition of pipe face 1 to be "exhuast fan" to describe the fan.

lovecraft22 · December 28, 2013, 08:52

Can't you just set an inlet and an outlet on the two sides of the fan?

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December 23, 2013, 13:49		#2
lovecraft22 Senior Member lore Join Date: Mar 2010 Location: Italy Posts: 460 Rep Power: 18	What is roadway #? Are you trying to simply simulate an exhaust within a domain?

December 23, 2013, 21:03		#3
kylin1282869061 New Member kylin Join Date: Sep 2013 Posts: 5 Rep Power: 13	thank you,lovecraft. the model is that a pipe is in another volume/domain(roadway),so there are two pairs of faces,namely 4 faces, they are pipe face 1 and roadway face 1, pipe face 2 and roadway face 2. now, if the boundary conditon of pipe face 1 is "exhasut",how to set the boundary conditon of roadway face 1 to let the air flow into the roadway??? hope for your reply.

December 24, 2013, 11:49		#5
lovecraft22 Senior Member lore Join Date: Mar 2010 Location: Italy Posts: 460 Rep Power: 18	Not sure I understand… you want air to be subtracted from the roadway and air to be added to the pipe but the air that goes out of the roadway is not the same air that enters the pipe, is that correct?

December 26, 2013, 12:48		#7
lovecraft22 Senior Member lore Join Date: Mar 2010 Location: Italy Posts: 460 Rep Power: 18	What is it like in the real case? Is there a fan there?

December 27, 2013, 22:46		#8
kylin1282869061 New Member kylin Join Date: Sep 2013 Posts: 5 Rep Power: 13	yes, there is a fan at the end of pipe face 1 and I just set the boundary condition of pipe face 1 to be "exhuast fan" to describe the fan.

December 28, 2013, 08:52		#9
lovecraft22 Senior Member lore Join Date: Mar 2010 Location: Italy Posts: 460 Rep Power: 18	Can't you just set an inlet and an outlet on the two sides of the fan?