Pipe flow calculators
Calculator Description
Compressible air flow and pressure drop calculator can be used for air flow through round closed pipe. Pressure drop or flow rate can be calculated, as temperature is considered to be constant.

Calculate:
 Pressure losses due to friction or local resistances
 Air flow rate
 Flow mean velocity
 Friction factor
 Reynolds number

Input:
 Pressure on the start or on the end of pipeline
 Weight or volumetric flow rate at standard conditions
 Inside pipeline diameter
 Pipeline length
 Air temperature
 Local resistance coefficient K
 Pipe surface roughness
Calculator Features
 Applicable for laminar and turbulent flow
 Pressure difference due to change of height is not included in this version of calculator
 Temperature is considered to be constant
Q: Calculate pressure drop created by air flow of 500 m^{3}/h in pipe line with 60 mm internal pipe diameter and pipe length of 100 m. Air temperature is 273 K, pipe roughness 0.02 mm, local resistances coefficient is 0.
A: Calculation setup:
Calculate for: pressure drop
Input one from following two:
p_{1}  absolute pressure on the pipe start
q  volumetric flow rate at normal conditions
Enter values:
q = 500 m^{3}/h
p_{1} = 6 bar
L = 100 m
D = 60 mm
T = 273 K
kr = 0.02 mm
Q: Calculate flow rate of air in pipe with internal diameter of 20 mm and length of 200 m. Created pressure drop is 2 bar. Internal pipe roughness is 0.02 mm and local resistances coefficient is 5.
A: Calculation setup
Calculate for: flow rate
Input one from following two:
p_{1}  absolute pressure on the pipe start
Enter values:
p_{1} = 6 bar
p_{1}  p_{2} = 2 bar
L = 200 m
D = 20 mm
T = 273 K
kr = 0.02 mm<
K = 5
Q: Calculate pressure drop created by air flow rate of 20 m^{3}/h at standard conditions in pipe with internal diameter of 5 mm, pipe length of 20 m pipe roughness of 0.02 mm and local resistance coefficient of 5.
A: Calculation setup:
Calculate for: pressure drop
Input one from following two:
p_{1}  absolute pressure on the pipe start
q  volume flow rate
Enter values:
q = 20 m^{3}/h
p_{1} = 16 bar
L = 20 m
D = 5 mm
T = 273 K
kr = 0.02
K = 5
Compressible air flow calculation is based on the pressure drop equation for isothermal flow:
Read more about used theory on compressible gas flow page.
If you experience problems with calculator start try to find answers on instructions page.
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