Can anyone help me on determining the flow rate of argon? 1

[haydenle]

I am an intern at a steel mill. I very new to this, so bear with me. I currently have a project to size a flowmeter. I know the pressure upstream is around 200psig, this is coming from and Airliquide vessel outside the plant. Down stream we have a pressure regulator and it is regulated down to 80 psig. The headlosses for the system will take forever to determine. The temperature leaving the vessel is -20 degrees F and I am not sure what the temp is at the regulator. Please any help would be greatly appreciated.

 

[haydenle]

Well, I tried a different approach. Tell me if I'm doing this right. Same approach, just solving for v1. This is at the exit point.

P1=(80+14.7)psia
T1=(70+460)R

P2=14.7psia
T2=(70+460)R

Here, I just assumed A1=A2. Then let V2=(rho1/rho2*V1). I end up with 452 ft/s for V1.

 

[iainuts]

Hi WayneLee. If you're trying to determine the velocity of flow through a pipeline due to pressure drop, Bernoulli's isn't needed and won't work. Only the continuity equation is needed (ie: mass flow per unit time = velocity x area x density). Of course, this means you have to accurately know all but one of the variables which from reading your thread seems like you don't.

If you're trying to determine mass flow from the available information, you're not going to get there. You don't have enough info. Pressure drop and frictional flow calculations are nicely summarized in the Crane Paper #410 and many other references, but Bernoulli's doesn't work for frictional flow, it is only a conservation of energy equation.

 

[BigInch]

Bernoulli's works for frictional flow when you include the head lost due to flow friction.

Going the Big Inch!

http://virtualpipeline.spaces.msn.com

 

[BigInch]

WayneLee,

This thread is getting too long and you still don't have the answer you need.

If you want to try to contact me directly, go to my webspace page, profiles tab and get my e-mail address. Send me a e-mail and I'll help you finish with this thing.



Going the Big Inch!

http://virtualpipeline.spaces.msn.com

 

[iainuts]

"Bernoulli's works for frictional flow when you include the head lost due to flow friction. "

That's the point, the calculations above don't include head loss due to flow. The point is that you can't determine flow or pressure drop without considering frictional flow. Besides which, trying to determine flow rate from pressure drop in a pipeline is fraught with inaccuracies.

PS: How long does a thread need to be before it is "too long"?

 

[BigInch]

I'd say after 4 or 5 stitches, it should be finishing up, or somebody needs to get on either MSMessenger or the telephone.

Going the Big Inch!

http://virtualpipeline.spaces.msn.com

 

[haydenle]

A thread is never too long.

 

[BigInch]

This one is. Look in your inbox.

Going the Big Inch!

http://virtualpipeline.spaces.msn.com