Calculating Flow rate for an oxygen system

[Fin8034]

TL;DR

flow rate of oxygen through a pipe from a pressurized cylinder to atmospheric pressure

I'm struggling with calculating the flow rate for an oxygen system.
There is a pressurised cylinder.
This then joins onto a pressure reducer.
Then travels down a length of pipe which branches off to 4 exits there is no restrictions on the exits it just goes to atmospheric pressure.

I am yet to find the specific values for each part of the system however, when i find out i will know the pressure in the cylinder, the volume of the cyclinder, the pressure that it is reduced to, the diameter of the pipe, and the length of the pipe.

im only looking for a rough answer to compare to other methods and testing as the system will also be modeled in ansys

any help would be appreciated.

 

[BvU]

Hello @Fin8034 , !

You ask a very general question without being specific about anything relevant. And without telling what you are starting from. If you have no subject knowledge at all, I propose you find a decent textbook. And stay away from Ansys until you know what you are doing (if ansys will be run by someone else, then that is the person to ask your general question on how to get started!).

Are you modelling big flows, small flows or leaking ? Do you know about isothermal and /or adiabatic expansion ? About pressure drop in a pipe system ?

 

[russ_watters]

How the system behaves and how you analyze it is going to heavily depend on the pressure and capacity of the regulator relative to the piping size. Can you provide those details?

 

[osilmag]

Flow rate is usually conserved entering and exiting an orifice. At the simplest level $\dot m = \rho V A$ at the entrance and exit. If you use energy: $\rho g h= .5 \rho v^2$ for a simple reservoir and opening.

 

[berkeman]

Summary:: flow rate of oxygen through a pipe from a pressurized cylinder to atmospheric pressure

I'm struggling with calculating the flow rate for an oxygen system.

Can you say what application this is for? Or is it a schoolwork exercise?

The design of oxygen delivery systems for healthcare facilities is not something to be done by an inexperienced person who is just learning the ropes. During the recent COVID-19 surges, hospitals have had trouble with $O_2$ delivery systems that were sized for use during normal times, not extreme surge conditions.

There have been instances of hospitals that had to move patients from upper floors into surge facilities on lower floors because the $O_2$ systems could not maintain full flow rate to the upper floors (the tanks are generally near ground level). And there were a couple instances of $O_2$ piping freezing because of too high a flow rate through too much restriction. Bad news when people's lives are on the line...