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Motivation


Explicit solution of  Pressure Profile in Homogeneous Steady-State Pipe Flow @model


Outputs


LaTeX Math Inline
bodyp(l)

Pressure distribution along the pipe

LaTeX Math Inline
bodyq(l)

Flowrate distribution along the pipe

LaTeX Math Inline
bodyu(l)

Flow velocity distribution along the pipe

Inputs


LaTeX Math Inline
bodyT_0

Intake temperature 

LaTeX Math Inline
bodyT(l)

Along-pipe temperature profile 

LaTeX Math Inline
bodyp_0

Intake pressure 

LaTeX Math Inline
body\rho(T, p)

LaTeX Math Inline
bodyq_0

Intake flowrate 

LaTeX Math Inline
body\mu(T, p)

LaTeX Math Inline
bodyz(l)

Pipeline trajectory TVDss

LaTeX Math Inline
bodyA

Pipe cross-section area  
LaTeX Math Inline
body\theta


Pipeline trajectory inclination,

LaTeX Math Inline
body--uriencoded--\displaystyle \cos \theta = \frac%7Bdz%7D%7Bdl%7D = \rm const

LaTeX Math Inline
body\epsilon

Inner pipe wall roughness

Assumptions


Stationary flowHomogenous flowIsothermal or Quasi-isothermal conditions

Constant cross-section pipe area

LaTeX Math Inline
bodyA
along hole

LaTeX Math Inline
body\theta (l) = \theta = \rm const

LaTeX Math Inline
bodyf(l) = f = \rm const

LaTeX Math Inline
body--uriencoded--\rho = \rho%5e* \cdot ( 1 + c%5e* \cdot p)



Equations


Pressure profile along the pipe


LaTeX Math Block
anchorPressureProfile
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L = \frac{1}{2 \, G \, c^*  \rho^*}  \cdot \ln \frac{G \, \rho^2-F}{G \, \rho_0^2-F}
-\frac{d}{f} \cdot \ln \frac{F/\rho^2 - G}{ F/\rho_0^2-G}



LaTeX Math Block
anchor1
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 \cos \theta \neq 0



LaTeX Math Block
anchorG0
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L = \frac{1}{2F\, c^* \rho^*} \cdot (\rho_0^2 - \rho^2)
 - \frac{2d}{f} \cdot \ln \frac{\rho_0}{\rho}



LaTeX Math Block
anchor1
alignmentleft
 \cos \theta = 0


where

LaTeX Math Inline
body--uriencoded--\displaystyle j_m = \frac%7B \dot m %7D%7B A%7D

mass flux

LaTeX Math Inline
body--uriencoded--\displaystyle \dot m = \frac%7Bdm %7D%7B dt%7D

mass flowrate

LaTeX Math Inline
body--uriencoded--\displaystyle q_0 = \frac%7BdV_0%7D%7Bdt%7D = \frac%7B \dot m %7D%7B \rho_0%7D

Intake volumetric flowrate

LaTeX Math Inline
body\rho_0 = \rho(T_0, p_0)

Intake fluid density 

LaTeX Math Inline
body\Delta z(l) = z(l)-z(0)

elevation drop along pipe trajectory

LaTeX Math Inline
body--uriencoded--f = f(%7B\rm Re%7D(T,\rho), \, \epsilon) = \rm const

Darcy friction factor 

LaTeX Math Inline
body--uriencoded--\displaystyle %7B\rm Re%7D(T,\rho) =\frac%7Bj_m \cdot d%7D%7B\mu(T,\rho)%7D

Reynolds number in Pipe Flow

LaTeX Math Inline
body\mu(T,\rho)

dynamic viscosity as function of fluid temperature 

LaTeX Math Inline
bodyT
 and density 
LaTeX Math Inline
body\rho

LaTeX Math Inline
body--uriencoded--\displaystyle d = \sqrt%7B \frac%7B4 A%7D%7B\pi%7D%7D = \rm const

characteristic linear dimension of the pipe

(or exactly a pipe diameter in case of a circular pipe)

LaTeX Math Inline
bodyG = g \, \cos \theta = \rm const

gravity acceleration along pipe 

LaTeX Math Inline
body--uriencoded--F = j_m%5e2 \cdot f/(2d) = F(l) = \rm const



Expand
titleDerivation


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See Derivation of Pressure Profile in GF-Proxy Pipe Flow @model



The 

LaTeX Math Block Reference
anchorG0
 equation for horizontal pipelines can be re-written in terms of explicit pressure:

LaTeX Math Block
anchorNKP03
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L = (\rho^*/F)  \cdot (p_0-p) \cdot (1+ 0.5 \, c^* \cdot (p+p_0))


See also


References


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