Page 1 of 1

Urgent help needed in calculating pipe diameter

Posted: Wed Nov 10, 2010 3:48 pm
by tamerbeeh
For natural gas , We have a flow rate (Q) of 850 m3/h and flow pressure of 5 bar , so i need to know the pipe diameter suitable for such specifications mentioned , also i want a clear detailed way of how to calculate it , Thanks

Re: Urgent help needed in calculating pipe diameter

Posted: Wed Nov 10, 2010 5:57 pm
by admin
You should calculate flow rate as
q=q1(p1/p)(T/T1)=850 x (1.013/6.013) x (288/288) = 143 m3/h

Here is the report that I have from http://www.pipeflowcalculations.com/flowrate/ calculator:

Pipe diameter calculator CALCULATION REPORT
1. volumetric flow rate (q): q = 143 m3/h
2. mass flow rate (w): w = 507.75873 kg/h
3. diameter (D): D = 50.287144 mm
4. velocity (v): v = 20 m/s
5. cross section area (A): A = 1986.1127 mm2
6. pressure of gas (p): p = 6.013 bar
7. density (ρ): ρ = 3.5507605 kg/m3
8. temperature (T): T = 288 K
9. gas constant (R): R = 588 J/kgK

Note that you have to select to input calculate for gas and temperature instead of density.

So input values are in bold above. Pressure is at absolute value. You can change velocity values but for 5 bar I use 20 m/s maximum. It also should be checked for pressure drop once pipe length is known.

You have theory for diameter calculation at:
http://www.pipeflowcalculations.com/pip ... locity.php.

Also, take care as density is changing with pressure and temperature like you have explained at:
http://www.pipeflowcalculations.com/pip ... ensity.php.

Hope this helps