boundaries conditions for an oil -gas separator

juliom · April 16, 2011, 11:20

I´m working hard to set up the boundaries conditios for an oil and gas separator. I just have the mas flow rate in the inlet, BUT I do not have the volume fraction in the inlet... Furthemore I do not know wich is th esuitable outlet condiont. For the outlet I set up them as an outlet with the static pressure as a 0 PSI..

PLEASEE HELP MEEEEEEE
Any information you could help me abut multiphase I will thank!!!

ghorrocks · April 17, 2011, 07:37

If you are guessing a parameter (eg inlet volume fraction) then it is a good idea to do a sensitivity check of that guess. This will tell you whether the parameter you guessed is important or not, and whether your results are rubbish.

By sensitivity check I mean do a VF much higher and much lower than you currently have and see if it changes the output of interest to you.

We can make no judgement about the suitability of your outlet with no description of the device you are modelling.

juliom · April 17, 2011, 12:23

Quote:

Originally Posted by ghorrocks

If you are guessing a parameter (eg inlet volume fraction) then it is a good idea to do a sensitivity check of that guess. This will tell you whether the parameter you guessed is important or not, and whether your results are rubbish.

By sensitivity check I mean do a VF much higher and much lower than you currently have and see if it changes the output of interest to you.

We can make no judgement about the suitability of your outlet with no description of the device you are modelling.

Hey dear glenn, It is very nice to know that you live in Australia, i´m planing to move there!!!.
Regarding to the topic, I am very sure what I am modelling. The point is that any standard ( API, GPSA among others) they do not establish how much is the pressure loss within the equipment.
As result I setting up the outlet condition as pressure of 0 PSI, with this information defined, I can find out the pressure required at the inlet, since the pressure in the inlet is part of the solution.
The most difficult part is define the VF in the inlet since I just have the flowrates of each phase..

I am mechanical engineer with a certificate in gas engineer, Furthermore I am doing my master degree (on CFD) thesys ... Indeed this is my thesys..
Here i let my Email if you want to contact me to talk more about this topic or if you have more information about multiphases simulation.

Julio_parker@hotmail.com

Your sincerely
Julio M

ghorrocks · April 17, 2011, 20:02

If you have the flow rates of each phase then use a mass flow inlet and your assumed 0 psi outlet. That is a good way to define the flow. Then the solver will determine the inlet pressure for you.

sincity · May 15, 2011, 07:11

hi, juliom...i'm going to do three phase horizontal separator (gas-oil-water), i have mass flow rate data...i confuse about what mixture model should i use and the boundary condition. i have my trial simulation with mixture model and mass flow inlet B.C for the inlet and outflow B.c for the outlet but it gave un reallistic contour of volume fraction...please help. i'm undergraduate student

April 16, 2011, 11:20	boundaries conditions for an oil -gas separator	#1
juliom Senior Member Julio Mendez Join Date: Apr 2009 Location: Fairburn, GA. USA Posts: 289 Rep Power: 17	I´m working hard to set up the boundaries conditios for an oil and gas separator. I just have the mas flow rate in the inlet, BUT I do not have the volume fraction in the inlet... Furthemore I do not know wich is th esuitable outlet condiont. For the outlet I set up them as an outlet with the static pressure as a 0 PSI.. PLEASEE HELP MEEEEEEE Any information you could help me abut multiphase I will thank!!!

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April 17, 2011, 07:37		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,480 Rep Power: 140	If you are guessing a parameter (eg inlet volume fraction) then it is a good idea to do a sensitivity check of that guess. This will tell you whether the parameter you guessed is important or not, and whether your results are rubbish. By sensitivity check I mean do a VF much higher and much lower than you currently have and see if it changes the output of interest to you. We can make no judgement about the suitability of your outlet with no description of the device you are modelling.

April 17, 2011, 20:02		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,480 Rep Power: 140	If you have the flow rates of each phase then use a mass flow inlet and your assumed 0 psi outlet. That is a good way to define the flow. Then the solver will determine the inlet pressure for you.

May 15, 2011, 07:11		#5
sincity Member wibi ario Join Date: Feb 2011 Posts: 46 Rep Power: 14	hi, juliom...i'm going to do three phase horizontal separator (gas-oil-water), i have mass flow rate data...i confuse about what mixture model should i use and the boundary condition. i have my trial simulation with mixture model and mass flow inlet B.C for the inlet and outflow B.c for the outlet but it gave un reallistic contour of volume fraction...please help. i'm undergraduate student