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Gas network design

Gas network design

Gas network design

(OP)
i need some good equation for calculatind the speed and the pressure drop in a gas network
 i have to made a network whit 60 nodes, about 2 km
 start presure 1,5 ata Q=3500 Nmc/h and at the end point of the network  presure  1,2 ata and Q at last user 300Nmc/h, i tried some software but whit unsatisfied result.
 

RE: Gas network design

You're probably not using the software correctly, or you need a better package.  There is no easy equation to do gas network design.  Its an iterative procedure that makes hand or spreadsheet calculations impractical for anything more than a 5-10 pipe network.

BigInchworm-born in the trenches.
http://virtualpipeline.spaces.msn.com

RE: Gas network design

(OP)
i have an execel program but i need some equation to calculate speed when i know reynolds and diameter but i dont know delta P for turbulent flow the spredsheet it,s like that:

Q    diameter    lenght   reynolds lamda  P1   P2    v(speed)


where i use reynolds=2230*(Q/diameter)
P1 =1,5 ata
P2 =P1-(lamda*lenght*v*v*rho)/2*diameter
lamda it's calculated whit precision of 7 digit after zero
using coolbrok formula

so i need V(speed)

thanks


RE: Gas network design

There are 3 unknowns.  Q, P1, P2

Use the network solver to calculate those, or eliminate 2 unknowns and solve for the remaining.

3 significant figures work quite well.

V = Q/A

BigInchworm-born in the trenches.
http://virtualpipeline.spaces.msn.com

RE: Gas network design

(OP)
thanks

in fact i know Q=3500 Nmc/h and P1=1.5 ata

RE: Gas network design

Then you have all the info you need, just find the actual volume flowing inside the pipe at both points/Area of flow.

Quick way is to convert the standard flowrate to actual flowing volume inside the pipe. To do that, get the compressibility factor z, then,
 
Vol_1 @ P1 & T1 = Vol_std x P1/P_atm x T1/T_std /z@P1&T1
Vol_2 @ P2 & T2 = Vol_std x P2/P_atm x T2/T_std /z@P2&T2

where z = compressibility factor

Velocity at point 1 = Vol_1/A1
Velocity at point 2 = vol_2/A2

An, the inside area of the pipe at point n.

BigInchworm-born in the trenches.
http://virtualpipeline.spaces.msn.com

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