Compressible Flow Analysis

[RJB32482]

I just want to check my engineering analysis on a nitrogen system.
Nitrogen is stored in an accumulator tank at 100 psig. It exits the accumulator then splits off in 3 branches. Each branch is designed for a different flow rate (60 CFM, 25 CFM, and 120 CFM). Here is how I am going about the analysis:
Calculate pressure drop through all 3 lines at design flow. Take the highest value of the 3. Then calculate the pressure drop from the tank to the branch point at the flow of 205 CFM. Add the 2 pressure drops. If its below 100 psi, we should be able to get the necessary flow. If not, then we need more pressure at the tank.

Thanks.

 

[BigInch]

Gotta have some control here.. if you're serious about your flowrates (see my first post).

Going the Big Inch!

http://virtualpipeline.spaces.msn.com

 

[Latexman]

BigInch,

Absolutely, then there is all that wasted N2 at the end of Pipe 1 and 2. It's not the way I'd approach it, but I kept it as simple as described to help the OP get his arms around it.


Good luck,
Latexman

 

[BigInch]

Gottcha'. No worries. Sometimes you just have to prove to the OP in the most direct way possible that they can't change physics.

Going the Big Inch!

http://virtualpipeline.spaces.msn.com

 

[sailoday28]

BigInch-I misunderstood and thought your equation
In each branch i,
Qi = Ki * (Pb^2-Po^2), for i = 1,2,3 was suggested.
It validity is for low velocity isothermal flow of a perfect gas.

Regards

 

[BigInch]

Sailor.. You're right, however I didn't consciously select it for applicability to this case. OK, neither did it look out of place when I wrote it, but I must admit that it was the first equation that came into my mind and I used it just to show a typical branch flow equation.

Going the Big Inch!

http://virtualpipeline.spaces.msn.com