Friction Factors F10

# Friction Factors F10 - D = Pipe or tubing inside diameter =...

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1 of 4 Friction Factors and Pressure Drop Calculations Two friction factors are commonly used to calculate friction losses in conduits. For circular ducts Darcy, Moody, or Blasius (names are interchangeable) 2 2 V P L D f D ρ Δ = Fanning 2 4 1 2 V P L D f F Δ = Darcy, Moody, or Blasius Friction Factor, f D The Darcy friction factor is a dimensionless pressure gradient, e D dL dP f * = 2 2 * V dP dP = head velocity head pressure D dL dL e = equivalent length Ο Ο Π Ξ Μ Μ Ν Λ Δ = Ο Ο Π Ξ Μ Μ Ν Λ = 2 2 2 2 V P L D dL D V dP f D 2 2 V D L f P D = Δ

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2 of 4 Fanning Friction Factor, f F The Fanning friction factor is a dimensionless wall shear stress * w F f τ = 2 2 * V w w ρ = wall shear stress expressed as number of velocity heads H w r dL dP = perimeter wetted area sectional - cross radius hydraulic = = H r Ο Ο Π Ξ Μ Μ Ν Λ Δ = Ο Ο Π Ξ Μ Μ Ν Λ = 2 2 2 2 V P L r dL r V dP f H H F For circular ducts 4 D r H = 2 4 1 2 V P L D f F Δ = 2 4 2 V D L f P F = Δ
3 of 4 Darcy, Moody, or Blasius Friction Factor and Pressure Drop Correlation 2 2 V D L f P D ρ = Δ where: Δ P = Pressure drop due to skin friction L = Length of flow path D f = Darcy friction factor, dimensionless

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Unformatted text preview: D = Pipe or tubing inside diameter = Fluid density ε = roughness parameter V = Average fluid velocity Re = Reynolds number Figure reproduced from: Technical Paper No. 410, Flow of Fluids through Valves, Fittings, and Pipes , Crane Co., NY, Appendix A-24, 1976. 4 of 4 Fanning Friction Factor and Pressure Drop Correlation 2 4 2 V D L f P F ρ = Δ where: Δ P = Pressure drop due to skin friction L = Length of flow path F f = Fanning friction factor, dimensionless D = Pipe or tubing inside diameter = Fluid density ε = roughness parameter V = Average fluid velocity Re = Reynolds number Figure reproduced from: Unit Operations of Chemical Engineering, 7 th ed. , W.L. McCabe, J.C. Smith, and P. Harriott, McGraw-Hill, NY, Fig. 5.10, p. 115, 2005....
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Friction Factors F10 - D = Pipe or tubing inside diameter =...

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