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Pipeline Flow Pressure Model is addressing this problem with account of the varying pipeline trajectory, gravity effects and fluid friction with pipeline walls.


Inputs & Outputs

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InputsOutputs

Pipeline trajectory

LaTeX Math Inline
body{\bf r} = {\bf r}(l) = \{ x(l), \, y(l), \, z(l) \}

along-pipe

 stabilised

 stabilized pressure distribution 

LaTeX Math Inline
bodyp(l)

Pipeline cross-section area 

LaTeX Math Inline
bodyA(l)

along-pipe

stabilised

stabilized flowrate distribution 

LaTeX Math Inline
bodyq(l)

Along-pipe temperature profile 

LaTeX Math Inline
bodyT(l)

along-pipe stabiliszed average flow velocity distribution 

LaTeX Math Inline
bodyu(l)
 

Fluid density

LaTeX Math Inline
body\rho(T, p)
and fluid viscosity 
LaTeX Math Inline
body\mu(T, p

)along-pipe stabilised average flow velocity distribution  LaTeX Math Inlinebodyu(l

)

 


inflow pressure 

LaTeX Math Inline
bodyp_0
, inflow rate 
LaTeX Math Inline
bodyq_0


Inner pipe wall roughness

LaTeX Math Inline
body\epsilon

flow temperature distribution 

LaTeX Math Inline
bodyT(l)

Assumptions

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Stationary fluid flowIsothermal or Quasi-isothermal conditions
Homogenous fluid flow

Constant cross-section pipe area

LaTeX Math Inline
bodyA(l)
along hole



Equations

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LaTeX Math Block
anchor9QRCZ
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\bigg( 1 -  \frac{c(p) \, \rho_0^2 \, q_0^2}{A^2}   \bigg )  \frac{dp}{dl} = \rho(p) \, g \, \frac{dz}{dl}  - \frac{\rho_0^2 \, q_0^2 }{2 A^2 d} \frac{f(p)}{\rho(p)}



LaTeX Math Block
anchor1
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u(l) = \frac{\rho_0 \cdot q_0}{\rho(p) \cdot A(l)}



LaTeX Math Block
anchor1
alignmentleft
q(l) = \frac{\rho_0 \cdot q_0}{\rho(p)}



(see Derivation of Stationary Isothermal Homogenous Pipe Flow Pressure Profile @model )

Approximations

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Incompressible

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pipe flow with constant friction


Pressure profilePressure gradient profileFluid velocityFluid rate


LaTeX Math Block
anchorH8MPT
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p(l) = p_0 + \rho \, g \, z(l) - \frac{\rho_0 \, q_0^2 }{2 A^2 d} \, f_0 \, l



LaTeX Math Block
anchorIFPGP
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\frac{dp}{dl} = \rho \, g \cos \theta(l) - \frac{\rho_0 \, q_0^2 }{2 A^2 d} \, f_0 



LaTeX Math Block
anchor1
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u(l) = \frac{q_0}{A(l)}



LaTeX Math Block
anchor1
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q(l) =q_0 = \rm const


where

LaTeX Math Inline
body\displaystyle \cos \theta(l) = \frac{dz(l)}{dl}

correction factor for trajectory deviation


The first term in 

LaTeX Math Block Reference
anchorIFPGP
defines the hydrostatic column of static fluid while the last term defines the friction losses under fluid movement:

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