Gas Flow Formula 1

[wonderlandinirvine]

Do anyone recognizes the following Gas Flow formula (for air here)?

W (lbs/sec) = 6.30*Cd* (d^2) *P1 /[(53.34*T)^0.5] * {3.5[(P2/P1)^1.429 - (P2/P1)^1.714]}^0.5

I would appreciate someone can point me to the source.

I understand one from "Crane":

qm' (SCFM) = 678 *Y *(d1^2)* C *{[deltaP*P1'/(T1Sg)]^0.5}

But they have gap and I do not know how to prove they are the same.

Thank you in advance for your kind help.

 

[BigInch]

You mean besids the gap caused by one being in actual mass flow rate of LBS/SEC and the other in standard volumetric cubic feet per MINUTE.

Assuming you have some kind of pipeline, I'd recommend against using any equation you can't find in this doc,

http://www.psig.org/papers/2000/0112.pdf

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[wonderlandinirvine]

Thank you for the reponse. I'm sorry that I forgot to mention this is gas flow equation for "orifice". I look at the paper you mention and find that is for "pipe". If you recognize the formula, please kindly let me know.

 

[vpl]

I don't have any idea where your top formula came from.

The formula from Crane in terms of W is W=1891[·]Y[·]d₁²[·]C[·][√]([Δ]P/V₁)

where C and Y are read off graphs on pages A20 and A21.

Although I really like Crane, you need to understand that their constants take into account all the unit conversion factors. This can make it difficult to do "eyeball" comparisons unless you really dig into the units to understand how the constant is obtained.

Patricia Lougheed

Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of the Eng-Tips Forums.

 

[BigInch]

Sorry, I don't do orifices.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/