Pipe Flow/Friction Factor Calculations I: (U.S. units)

for given flow rate, Q, pipe diam., D, pipe length, L,

Inputs Calculations

6 in 0.5000 ft

0.0005 ft 0.01962

100 ft 0.1963

0.600 cfs 3.1 ft/sec

1.94 109,782

0.000027

2. Check on whether the given flow is "completely turbulent flow"

(Calculate f with the transition region equation and see if differs from the one calculated above.)

Transition Region Friction Factor, f: f = 0.0221

Repeat calc of f using new value of f: f = 0.0220

Repeat again if necessary: f = 0.0220

Calculation of Head Loss, hL, or Frictional Pressure Drop, DPf,

pipe roughness, e, and fluid properties, r & m.

1. Determine Friction Factor, f, assuming completely turbulent flow [f = 1.14 + 2 log10(D/e)-2]

Pipe Diameter, D = Pipe Diameter, D =

Pipe Roughness, e = Friction Factor, f =

Pipe Length, L = Cross-Sect. Area, A = ft2

Pipe Flow Rate, Q = Ave. Velocity, V =

Fluid Density, r = slugs/ft3 Reynolds number, Re =

Fluid Viscosity, m = lb-sec/ft2

f = {-2*log10[((e/D)/3.7)+(2.51/(Re*(f1/2))]}-2

0.6 ft

Frictional Pressure

40 psf

Frictional Pressure

0.28 psi

3. Calculate hL and DPf, using the final value for f calculated in step 2

(hL = f(L/D)(V2/2g) and DPf = rghL)

Frictional Head Loss, hL

Drop, DPf

Drop, DPf