| ID | 20231212203920 | Name | EngScript | Count | 138 |
| Title | Crane differential pressure or flow rate for compressible fluid (Imperial) |
| Keyword | Crane, DP, Compressible |
| Description | This Python code calculates differential pressure or flow rate according to given pipe & fitting information for compressible fluid.
Formula of DP and flow rate
Calculate differential pressure in pipes based on information on the following pipes/accessory equipment
w : Flow rate [lb/hr]
△P : Delta Pressure [psia]
L : Length [ft]
D : Pipe Diameter [ft]
d : Pipe Diameter [in]
ρ : Density [lb/ft3]
f : Friction factor
Here, Friction factor (f) must be calculated using separate charts and programs.
Calculation formulas based on CRANE BOOK
Kpipe = f * l/D
K = Kpipe + Kfitting
compressible fluid
△P = (K * W^2) / (1891^2 * d^4 * ρ * Y^2)
w = 1891 * d^2 * √(△P * ρ / K) * Y
liquid fluid
△P = (K * W^2) / (1891^2 * d^4 * ρ)
w = 1891 * d^2 * √(△P * ρ / K)
Python code
import math
def compressibledp(W, l, d, r, Y, f, Kf):
D = d * 12
Kp = f*l/D
K = Kp + Kf
dp = (K*pow(W, 2))/(pow(1891, 2)*pow(d, 4)*r*pow(Y, 2))
return dp
W = 220 # Flow rate (W, lb/hr)
l = 30.48 # Length (L, ft)
d = 1.969 # Pipe Diameter (d, in)
r = 0.0774 # Density (ρ, lb/ft3)
Y = 1.0 # Net Expansion Factor (Y)
f = 0.005 # Friction factor (f)
Kf = 500 # Resistance coefficient of fittings
dp = compressibledp(W, l, d, r, Y, f, Kf)
print("delta pressure of pipe = ", dp, "psia")
def compressibleflow(dp, l, d, r, Y, f, Kf):
D = d * 12
Kp = f * l / D
K = Kp + Kf
W = 1891 * pow(d, 2) * math.sqrt(dp * r / K) * Y
return W
dp = 5.933 # Delta Pressure (△P, psia)
m = 30.48 # Length (L, ft)
d = 1.969 # Pipe Diameter (d, in)
r = 0.0774 # Density (ρ, lb/ft3)
Y = 1 # Net Expansion Factor (Y)
f = 0.005 # Friction factor (f)
Kf = 500 # Resistance coefficient of fittings
flow = compressibleflow(dp, l, d, r, Y, f, Kf)
print("mass flow of pipe = ", flow, "lb/hr")
When run the code, you will receive the following results. delta pressure of pipe = 5.82 psia
mass flow of pipe = 222 lb/hr
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