pressure drop within a pipe

October 18, 2001, 13:10

Hello everyone!

My case is: Upward flow of air, within a pipe.I have set the external pressure eq to 0(relative to 1.0e5)and inlet velocity 2m/s, but the results are not logical.i.e. -1.0E-7(pa) at the bottom and 3.0e-5 at the top. Is there any specific setting that i haven't do correctly? Looking forward to your help. Thank you!

October 18, 2001, 22:43

Is your velocity field pointing in the correct direction ?

The pressure differential desribed seems to suggest that the flow is actual flowing down the pipe noy up it.

Try reversing the direction of the velocity of the air going up the pipe.

Habe you set the top of th pipe as an outlet / fixed pressure bouandary so that the air can flow out of the domain ? If not the air would tend to reverse diretion.

I hope this helps

Leon

October 22, 2001, 13:58

Leon's advice sounds good!

Are you sure it is fully converged?

By the way - is the density constant?

David

October 23, 2001, 04:51

The direcrtion of the air flow is up-wards, there is an outlet at the top af the pipe and the pressure tis set to 0(RElaative to 1e+5). yes, the dencity is constant, but i still have the same problem. Is there somethin g i can do about it?

Thank you for your help

November 6, 2001, 09:00

You must have done something wrong!

Are you using VR?

If you set it up with VR, it's very simple - an inlet, and outlet, and plate(s) for wall friction. You can set it up in 5 minutes and it will work fine.

February 6, 2002, 13:04

Is bouyancy turned on? Is the value of the gravitational constant correct?

October 18, 2001, 13:10	pressure drop within a pipe	#1
Liouskos Jiannis Guest Posts: n/a	Hello everyone! My case is: Upward flow of air, within a pipe.I have set the external pressure eq to 0(relative to 1.0e5)and inlet velocity 2m/s, but the results are not logical.i.e. -1.0E-7(pa) at the bottom and 3.0e-5 at the top. Is there any specific setting that i haven't do correctly? Looking forward to your help. Thank you!

October 18, 2001, 22:43	Re: pressure drop within a pipe	#2
leon Guest Posts: n/a	Is your velocity field pointing in the correct direction ? The pressure differential desribed seems to suggest that the flow is actual flowing down the pipe noy up it. Try reversing the direction of the velocity of the air going up the pipe. Habe you set the top of th pipe as an outlet / fixed pressure bouandary so that the air can flow out of the domain ? If not the air would tend to reverse diretion. I hope this helps Leon

October 22, 2001, 13:58	Re: pressure drop within a pipe	#3
David Glynn Guest Posts: n/a	Leon's advice sounds good! Are you sure it is fully converged? By the way - is the density constant? David

October 23, 2001, 04:51	Re: pressure drop within a pipe	#4
Liouskos Jiannis Guest Posts: n/a	The direcrtion of the air flow is up-wards, there is an outlet at the top af the pipe and the pressure tis set to 0(RElaative to 1e+5). yes, the dencity is constant, but i still have the same problem. Is there somethin g i can do about it? Thank you for your help

November 6, 2001, 09:00	Re: pressure drop within a pipe	#5
David Glynn Guest Posts: n/a	You must have done something wrong! Are you using VR? If you set it up with VR, it's very simple - an inlet, and outlet, and plate(s) for wall friction. You can set it up in 5 minutes and it will work fine.

February 6, 2002, 13:04	Re: pressure drop within a pipe	#6
PattiMichelle Guest Posts: n/a	Is bouyancy turned on? Is the value of the gravitational constant correct?

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