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Step by Step procedure to do Line sizing and pressure drop calculation for single phase of fluid flowing through a pipe. Criterion for Line size selection is generally pressure drop expressed as ǻP per 100 feet or meters of pipe. In certain services, velocity is used as governing principle. Step 1 Calculate Fluid Velocity Estimate an initial pipe diameter (D) and calculate Velocity (V) of fluid flowing through pipe using following equation : V = M / (ȡ *(ʌD²/4) ) where, M, Fluid mass flowrate ȡ, Density of fluid flowing through pipe Step 2 Determine Reynold's Number Reynold's number (Re) is calculated using following equation : Re = D * V * ȡ / ȝ where, ȝ, Viscosity of fluid flowing through pipe Step 3 Determine Friction Factor For Reynold's Number <= 2100 flow regime is Laminar. Friction factor can be estimated as following : f = 64 / Re For 2100 < Reynold's Number < 4000, flow regime is Transitional. Friction factor can be estimated using Churchill equation : where, İ, Pipe Roughness Churchill equation is valid over entire range of Reynold's number from Laminar to turbulent. For Reynold's Number > 4000 flow regime is Turbulent. Friction factor can be estimated using Colebrook White equation : Colebrook-White equation is implicit in f and can be solved by iterative procedure. Make an initial guess of friction factor and then use colebrook-white equation to get a new estimate. Repeat the step with new friction factor and after 5 to 10 iterations friction factor value will not change. Page 1 of 3 Line Sizing Single Phase 7/27/2014 http://checalc.com/guide/linesize.html Click to buy NOW! P D F - X C h a n g e w w w . d o c u - t r a c k . c o m Click to buy NOW! P D F - X C h a n g e w w w . d o c u - t r a c k . c o m

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  • Step by Step procedure to do Line sizing and pressure drop calculation for single phase of fluid flowing through a pipe.

    Criterion for Line size selection is generally pressure drop expressed as ?P per 100 feet or meters of pipe. In certainservices, velocity is used as governing principle.

    Step 1

    Calculate Fluid Velocity

    Estimate an initial pipe diameter (D) and calculate Velocity (V) of fluid flowing through pipe using following equation :

    V = M / (? * (?D/4) )

    where,

    M, Fluid mass flowrate

    ?, Density of fluid flowing through pipe

    Step 2

    Determine Reynold's Number

    Reynold's number (Re) is calculated using following equation :

    Re = D * V * ? / ?

    where,

    ?, Viscosity of fluid flowing through pipe

    Step 3

    Determine Friction Factor

    For Reynold's Number

  • Step 4

    Calculate Pressure Drop

    Pressure Drop (?P) is calculated based on Darcy-Weisbach equation :

    where,

    L, Pipe Length

    Step 5

    Check Pressure Drop

    Check whether pressure drop is within allowable limits, if it is higher than the allowable pressure drop increase the pipediameter and repeat from step 1.

    References1. Darcy friction factor formulae at Wikipedia2. Darcy Weisbach equation at Wikipedia

    Visit

    Calculation Spreadsheet

    Pipe internal diameter for 6" Sch40 pipe is 154.051 mm.

    Calculate Fluid Velocity

    V = 1.753 m/s

    Determine Reynold's Number

    Re = 22,958

    Determine Friction Factor

    Flow regime is Turbulent, Re > 4000. Solving Colebrook-White equation iteratively, after 6 iterations f value does notchange

    Fuel Oil having density 850 Kg/m and viscosity of 10 cP is being pumped through a 1 Km long 6", Sch 40 pipe atthe rate of 100,000 Kg/h. What is the pressure loss through pipe ? Pipe roughness is 0.045 mm.

    Example

    Page 2 of 3Line Sizing Single Phase

    7/27/2014http://checalc.com/guide/linesize.html

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  • f = 0.0257

    Calculate Pressure Drop

    Using Darcy-Weisbach equation, pressure drop is

    ?P = 2.18 bar

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    Page 3 of 3Line Sizing Single Phase

    7/27/2014http://checalc.com/guide/linesize.html

    Click

    to bu

    y NOW

    !PD

    F-XChange

    www.docu-track

    .com C

    lick t

    o buy

    NOW

    !PD

    F-XChange

    www.docu-track

    .com