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Motivation


One of the key challenges in Pipe Flow Dynamics is to predict the along-hole pressure distribution during the stationary fluid transport.

In many practical cases the stationary pressure distribution can be approximated by Isothermal or Quasi-isothermal homogenous fluid flow model.

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


InputsOutputs

Pipeline trajectory

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

along-pipe distribution of stabilised pressure 

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bodyp(l)

Pipeline cross-section area 

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bodyA(l)

along-pipe distribution of stabilised flow rate 

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bodyq(l)

Fluid density

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

along-pipe distribution of stabilised average flow velocity 

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bodyu(l)
 

Inner pipe wall roughness

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body\epsilon


Assumptions


Stationary fluid flow
Homogenous fluid flow
Isothermal or Quasi-isothermal conditions

Constant cross-section pipe area

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bodyA(l)
along hole



Equations




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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)}



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u(l) = \frac{\rho_0 \cdot q_0}{\rho(p) \cdot A(l)}



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q(l) = \frac{\rho_0 \cdot q_0}{\rho(p)}



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

Approximations



Incompressible fluid with constant friction


Pressure profilePressure gradient profileFluid velocityFluid rate


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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



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



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u(l) = \frac{q_0}{A(l)}



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q(l) =q_0 = \rm const


where

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

correction factor for trajectory deviation


The first term in 

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


In most practical applications in water producing or water injecting wells the water can be considered as incompressible and friction factor  an be assumed constant

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body f(l) = f_s = \rm const
 along-hole ( see  Darcy friction factor in water producing/injecting wells ).



References


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