| CALC : Flow : Friction 023 : Turbulent Liquid Flow Friction Pressure Loss From Flow Rate Multiple Section : Calculator
Description : Calculate the friction pressure loss ΔPf from the flow rate Q for turbulent liquid flow in a multiple section pipeline.
Discussion : The fluid density and viscosity are assumed to be constant along the pipeline. The k factor values account for the minor losses due to bends tees and valves etc in each section. The k values should be relative to the section diameter. The function CalcFMoody() calculates the Darcy friction factor f from the Reynolds number Re and the relative roughness Rr. For turbulent flow check that the Reynolds number 2000 < Re.
Note : To change the number of sections select the number of sections from the select box on the setup page.
Figures :
Input Variables :
- μ = Fluid Dynamic Viscosity
- ρ = Fluid Density
- D = Section Internal Diameter
- K = Dimensionless Friction Pressure Loss Factor K
- L = Section Length
- Q = Fluid Volume Flowrate
- Zi = Pipeline Inlet Elevation Above Datum
- Zo = Pipeline Outlet Elevation Above Datum
- g = Standard Gravity Acceleration At Sea Level
- r = Section Internal Roughness
Output Variables :
- ΔP = Fluid Static Pressure Difference
- ΔPf = Fluid Friction Pressure Loss
- ΔPfs = Section Friction Pressure Loss
- Re = Section Dimensionless Reynolds Number
- Rr = Section Dimensionless Internal Roughness Number
- V = Section Fluid Velocity
- f = Dimensionless Darcy Friction Pressure Loss Factor f
Calculation :
Loop i
V[i] = ( 4 Q ) / ( π D[i] 2 )
Re[i] = ( ρ V[i] D[i] ) / μ
Rr[i] = r[i] / D[i]
f[i] = CalcFMoody( Re[i] , Rr[i] )
ΔPfs[i] = ( f[i] L[i] / D[i] + K[i] )( ρ V[i] 2 ) / 2
End of i Loop
ΔPf = ArraySum( ΔPfs )
ΔP = ΔPf + ρ g ( Zo - Zi ) + ρ / 2 ( V[3] 2 - V[1] 2 )
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