Pressure Drop calculation

shubham208011 · July 17, 2013, 06:44

Hi all,

I am little bit confused in setting up problem for pressure drop calculation in Fluent. I am using Ansys Fluent 13.0

Can anyone please help me out in choosing the correct boundary condition.

Jim87 · July 17, 2013, 06:58

what do you want to simulate? Messure the pressure drop between two parts of a pipe?

shubham208011 · July 17, 2013, 07:05

Yes I want to simulate the pressure drop in a pipe

Jim87 · July 17, 2013, 07:14

the easiest way is to set to monitors at the reference Areas. If both outputs are set to statistic pressure the difference is your drop pressure.

If the simulation is alreaddy done you can use the report function

shubham208011 · July 17, 2013, 07:22

Doubt I have is in setting up the problem.

Suppose we chose velocity inlet boundary condition at inlet and pressure-outlet condition at outlet. Suppose pipe is open to atmosphere we chose 0 pa for gauge pressure at outlet or if we have any other value measured by pressure transducer experimentally.

Now here my doubt arises. Since we already fixed the pressure value at outlet then what is the meaning of pressure drop???

I am saying anything foolish please pardon me and explain me the correct version.

thanks

Jim87 · July 17, 2013, 08:34

okay. You have a open channel flow and don't know your exact outflow pressure. You may use the outfow boundary condition (Guide 7.3.10). This is a condition for unknown outflow pressure and velocity. It isn't awailable for every setting, you need to check the case in this chapture.

shubham208011 · July 17, 2013, 08:53

That's the problem. Actually I am trying to model multiphase flow (solid-gas) in pipe. I am using eularian model for it. But according to fluent user guide outflow boundary condition is not compatible with eularian multiphase model. I have the values at inlet but I don't have any values for outlet. Although I can theoretically calculate the value of pressure drop from empirical relations available in various literature. From this I can get the pressure value at outlet and put it in fluent.

Then things come in my mind that why I am doing simulation for pressure drop in fluent when i am using empirical relations.

Jim87 · July 17, 2013, 10:00

It might be okay if you set the pressure outlet to a reference value (1 bar) and solve what pressure the project needs to realise your inlet velocity. If you take the diference between Inlet and Outlet pressure this should work too.

shubham208011 · July 17, 2013, 10:44

Ok..

Do you have any idea what will happen if I use outflow boundary condition at the outlet for eularian multiphase flow??

I have some published research papers in which author has used outflow boundary condition for eularian multiphase simulation. I can share those with you if you want..

nikhilchotai@gmil.com · November 24, 2015, 05:27

As I m also doing same type of Problem but I stucked and if got solution then Please send me

nikhilchotai@gmail.com

Thank you

hadial · March 30, 2016, 15:15

hello every one:
I am simulating air flow in a channel using periodic BC in fluent:
I need to calculate pressure drop to calculate friction factor in my channel.
the air enters the channel with 0.3 Mpa pressure.
now the question is :
How can I calculate pressure drop across the length of a periodic duct?

I t is really urgent if anyone can help me I will be really greatful

July 17, 2013, 06:44	Pressure Drop calculation	#1
shubham208011 Member shubham Join Date: Mar 2009 Posts: 48 Rep Power: 17	Hi all, I am little bit confused in setting up problem for pressure drop calculation in Fluent. I am using Ansys Fluent 13.0 Can anyone please help me out in choosing the correct boundary condition.

July 17, 2013, 08:53		#7
shubham208011 Member shubham Join Date: Mar 2009 Posts: 48 Rep Power: 17	That's the problem. Actually I am trying to model multiphase flow (solid-gas) in pipe. I am using eularian model for it. But according to fluent user guide outflow boundary condition is not compatible with eularian multiphase model. I have the values at inlet but I don't have any values for outlet. Although I can theoretically calculate the value of pressure drop from empirical relations available in various literature. From this I can get the pressure value at outlet and put it in fluent. Then things come in my mind that why I am doing simulation for pressure drop in fluent when i am using empirical relations. Abhi.shek likes this.

November 24, 2015, 05:27	If got Answer Please send me detils i m having same problem	#10
nikhilchotai@gmil.com New Member Chotai Nikhil Join Date: Aug 2015 Posts: 7 Rep Power: 11	As I m also doing same type of Problem but I stucked and if got solution then Please send me nikhilchotai@gmail.com Thank you

March 30, 2016, 15:15	pressure drop in a channel using periodic boundary condition	#11
hadial New Member hadi Join Date: Jun 2015 Posts: 12 Rep Power: 11	hello every one: I am simulating air flow in a channel using periodic BC in fluent: I need to calculate pressure drop to calculate friction factor in my channel. the air enters the channel with 0.3 Mpa pressure. now the question is : How can I calculate pressure drop across the length of a periodic duct? I t is really urgent if anyone can help me I will be really greatful Abhi.shek likes this.

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July 17, 2013, 06:58		#2
Jim87 Member Stephan Langenberg Join Date: Sep 2011 Location: Germany Posts: 73 Rep Power: 15	what do you want to simulate? Messure the pressure drop between two parts of a pipe?

July 17, 2013, 07:05		#3
shubham208011 Member shubham Join Date: Mar 2009 Posts: 48 Rep Power: 17	Yes I want to simulate the pressure drop in a pipe

July 17, 2013, 07:14		#4
Jim87 Member Stephan Langenberg Join Date: Sep 2011 Location: Germany Posts: 73 Rep Power: 15	the easiest way is to set to monitors at the reference Areas. If both outputs are set to statistic pressure the difference is your drop pressure. If the simulation is alreaddy done you can use the report function

July 17, 2013, 07:22		#5
shubham208011 Member shubham Join Date: Mar 2009 Posts: 48 Rep Power: 17	Doubt I have is in setting up the problem. Suppose we chose velocity inlet boundary condition at inlet and pressure-outlet condition at outlet. Suppose pipe is open to atmosphere we chose 0 pa for gauge pressure at outlet or if we have any other value measured by pressure transducer experimentally. Now here my doubt arises. Since we already fixed the pressure value at outlet then what is the meaning of pressure drop??? I am saying anything foolish please pardon me and explain me the correct version. thanks

July 17, 2013, 08:34		#6
Jim87 Member Stephan Langenberg Join Date: Sep 2011 Location: Germany Posts: 73 Rep Power: 15	okay. You have a open channel flow and don't know your exact outflow pressure. You may use the outfow boundary condition (Guide 7.3.10). This is a condition for unknown outflow pressure and velocity. It isn't awailable for every setting, you need to check the case in this chapture.

July 17, 2013, 10:00		#8
Jim87 Member Stephan Langenberg Join Date: Sep 2011 Location: Germany Posts: 73 Rep Power: 15	It might be okay if you set the pressure outlet to a reference value (1 bar) and solve what pressure the project needs to realise your inlet velocity. If you take the diference between Inlet and Outlet pressure this should work too.

July 17, 2013, 10:44		#9
shubham208011 Member shubham Join Date: Mar 2009 Posts: 48 Rep Power: 17	Ok.. Do you have any idea what will happen if I use outflow boundary condition at the outlet for eularian multiphase flow?? I have some published research papers in which author has used outflow boundary condition for eularian multiphase simulation. I can share those with you if you want..