Pipe flow calculators
Calculator Description
Calculator can be used for resistance coefficient (or resistance factor) K and equivalent length l/d calculation for valves and fittings.

Calculate:
 Resistance coefficient K

Select:
 Fitting type
 Fitting shape and diameter
Calculator Features
 Applicable for bends, tees, reducers, entrance and exits
 For liquids and gases
Resistance coefficient and equivalent length l/d calculator should be used with pressure drop calculator or with gas compressible flow calculator to calculate pressure drop in piping system that includes obstructions like fittings and valves.
Based on the size and shape of valves and fittings different values for resistance coefficient and equivalent length l/d are calculated. Calculator can be used for elbows, pipe bends, mitre bends, return bends, standard tee, pipe entrance, pipe exit and for sudden and gradual enlargement or contraction of pipe.
Q: Calculate resistance coefficient K for 90^{O} 1 inch elbow with radius to diameter ratio R/D = 1.5
A: Calculation setup:
Input values:
R/D = 1.5
D = DN25
n = 1
Q: Calculate resistance coefficient for fluid flowing from resevoir to pipeline with pipe inward projecting to reservoir
A: Calculation setup:
Input values:
Type = inward projecting
Q: Calculate resistance coefficient for gradual enlargement and contraction. Angle of reducer is 30^{0}. Pipe diameters are 100 mm and 150 mm.
A: Calculation setup:
Input values:
Alfa = 30^{0}
D_{1} = 100 mm
D_{2} = 150 mm
Resistance coefficient value is used for pressure drop calculation using following formula:
Read more about used theory on flow in pipes page.
If you experience problems with calculator start try to find answers on instructions page.
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