Motivation


One of the key challenges in Pipe Flow Dynamics is to predict the pressure distribution along the pipe 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.


Outputs


Pressure distribution along the pipe

Flowrate distribution along the pipe

Flow velocity distribution along the pipe

Inputs


Intake temperature 

 Fluid density

Intake pressure 

Intake flowrate 

Pipeline trajectory TVDss


 Inner pipe wall roughness




Assumptions


Steady-State flowIsothermal

Homogenous flow

Constant cross-section pipe area along hole

Incompressible fluid 

 → 


Equations


Pressure profilePressure gradient profile
p(l) = p_0 + \rho_0 \, g \, \Delta z(l) - \frac{\rho_0 \, q_0^2 }{2 A^2 d} \, f_0 \, l = p_0 + \rho_0 \, g \, \Delta z(l) - \frac{8}{\pi^2} \frac{f_0 \, l}{d^5} \rho_0 \, q_0^2
\frac{dp}{dl} = \rho_0 \, g \cos \theta(l) - \frac{\rho_0 \, q_0^2 }{2 A^2 d} \, f_0
Mass FluxMass Flowrate

j_m = \rho_0 \cdot \sqrt{\frac{2 \, d}{f_0 \, l }} \cdot \sqrt{g \, \Delta z(l) + (p_0 - p)/ \rho_0}
\dot m = j_m \cdot A = \rho_0 \cdot A \cdot \sqrt{\frac{2 \, d}{f_0 \, l }} \cdot \sqrt{g \, \Delta z(l) + (p_0 - p)/ \rho_s}

 Volumetric Flowrate

Intake Fluid velocity

q_0 = \dot m / \rho_0 = A \cdot \sqrt{\frac{2 \, d }{ f_0 \, l }} \cdot \sqrt{  g \, \Delta z(l) + (p_0 - p)/ \rho_0 }
u_0 = j_m/ \rho_0 =q_0 / A = \sqrt{\frac{2 \, d }{ f_0 \, l }} \cdot \sqrt{  g \, \Delta z(l) + (p_0 - p)/ \rho_s }


where

Intake mass flux

mass flowrate

Intake Fluid velocity

elevation drop along pipe trajectory

Darcy friction factor at intake point

Reynolds number at intake point

characteristic linear dimension of the pipe

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



Incompressible fluid  means that compressibility vanishes  and fluid velocity is going to be constant along the pipeline trajectory .

For the constant viscosity  along the pipeline trajectory the Reynolds number  and Darcy friction factor  are going to be constant along the pipeline trajectory.

Equation  becomes:

\frac{dp}{dl} = \rho_0 \, g \, \frac{dz}{dl}  - \frac{j_m^2  f_0}{2 \, \rho_0 \, d}

which leads to  after substituting   and can be explicitly integrated leading to .


The first term in the right side of 
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, water can be considered as incompressible and friction factor  can be assumed constant  along-hole ( see  Darcy friction factor in water producing/injecting wells ).


See also


Physics / Fluid Dynamics / Pipe Flow Dynamics / Pipe Flow Simulation / Pressure Profile in Homogeneous Quasi-Isothermal Steady-State Pipe Flow @model

Pressure Profile in Incompressible Quasi-Isothermal Proxy Pipe Flow @model ]

Darcy friction factor ] [ Darcy friction factor @model ] 

Homogenous Pipe Flow Temperature Profile @model ]



References


PipeFlowSimulator.xls
Pressure loss in pipe @ neutrium.net 
R. Shankar, Pipe Flow Calculations, Clarkson University [PDF]
Pressure loss in chokes @ Studopedia