What is the pressure?

[EHE]

Given: Fluid Natural Gas, turbulent flow in a pipe section at point A, Pipe inside dia ID, Flowrate W, Temperature T, Z factor Z, Molecular weight MW, Gas Constant R. Could the pressure be estimated from the above data? Anyone is familiar with this formula: P=(58742)*(W/Area) *(ZRT/MW)^.5
W lb/hr; area in^2; R 10.73; T deg R. What is its origine.
Cheers,

 

[JStephen]

Looks to me like you're still missing something. If you had a flow velocity AND the mass flow rate, you could figure density and go from there.

Volumetric flow rate = average velocity x cross section area
Mass flow rate = velocity x area x density
= velocity x area/ specific volume
Or W = V x A / v
Or W/A = V/v or 1/v = (W/A)/V

Ideal gas law- Pv = RT or
P = RT/v = RT(W/A)/V = (W/Area) x (RT) x 1/V

Now, this isn't the same as what you indicated, so I don't know where the difference lies.
The Z factor is added for non-perfect gas behavior. The molecular weight would be to convert from universal gas constant to specific gas constant.

You don't indicate the actual wording of the problem (sounds like homework problem), so hard to say where the difference comes in.

Due to friction in a pipe, gas tends to either speed up or slow down to the sonic speed in the pipe. If this is an assumed condition that isn't stated, the equation above may be based on that assumption. I forget right offhand what the speed of sound is for an ideal gas, but try substituting in the equation above if appropriate.

 

[sailoday28]

It looks like a formula for isothermal flow.
Refer to "The Dynamics and Thermodynamics of Compressible Fluid Flow" Volume 1 Ascher H. Shapiro The Roland Press Company pg 183 Equation 6.44
The formula is for a perfect gas. Therefore, replace R by ZR

gamma*mach^2=(W/A)^2*RT/p^2

which basically is the form of your equation. I will leave it up to you to put proper units into the equation of Shapiro. ie, typically KE is written vel^2/2.