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Mass flow rate through bottle

Mass flow rate through bottle

(OP)
Dear All, I have a question and hope that you know answer
I have one vessel which is in 207 barg and full of air. there is pipeline which comes from vessel and there is hand valve at the end of the pipeline. in order to fill small air bottle, I will plugged air bottle to line and will open the hand valve. now, air will flow from 207 barg to air bottle. in initial state for example, air will flow from 207 barg to atmospheric pressure, after some time as bottle pressure increases, air will flow from 207 barg to 200 barg ( as an example) (I assumed vessel constant pressure)
from statement above, it is understandable that mass flow rate from tank to bottle will change as pressure of bottle increases. I need to calculate mass flow rate in each second and finally to find time to fill bottle to 200 barg for example. could you please help me? giving any equation which can be used to calculate mass flow rate or time for filling?

RE: Mass flow rate through bottle

Tarlan,

Please don't double post or add new questions in a different post / forum without referring to your other posts as a minimum otherwise you get two sets of answers and people asking the same questions.

You can only work this out knowing what the flow restrictor is and what the flow figure is on the regulator. only when you know that data can you work out the mass flow.

given this is the same thing, you don't have a vessel at 207, you have a constant pressure supply which is something quite different.

For anyone interested in this question, see this post which appears to be same question. http://www.eng-tips.com/viewthread.cfm?qid=428813

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Mass flow rate through bottle

(OP)

" given this is the same thing, you don't have a vessel at 207, you have a constant pressure supply which is something quite different."

I am very sorry , but why quite different? in terms of calculation cant we consider as the same process?

RE: Mass flow rate through bottle

Because a vessel will instantly start to lose pressure as it fills the smaller container. A fixed pressure feed will stay constant.

If it is a vessel then you need to know the relative volumes.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Mass flow rate through bottle

(OP)
LittleInch,

but in my post, I said " imagine vessel supply pressure is constant" in this case, aren't they same thing?

RE: Mass flow rate through bottle

But you cannot "imagine" anything in the real world. The real world does not work like a textbook (unlike what college professors write for the questions and homework assignments). The real world has real dimensions, volumes, and pressure losses as a larger, real world high pressure vessel empties into a smaller vessel at lower pressure..

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