Page tree

Versions Compared

Key

  • This line was added.
  • This line was removed.
  • Formatting was changed.


Motivation


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

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

Pressure Profile in L-Proxy Pipe Flow @model is addressing this problem with account of the varying pipeline trajectory, gravity effects and fluid friction with pipeline walls.


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 (l)


Pipeline trajectory inclination,

LaTeX Math Inline
body--uriencoded--\displaystyle \cos \theta (l) = \frac%7Bdz%7D%7Bdl%7D

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


Equations


Pressure profile along the pipe


LaTeX Math Block
anchorPressureProfile
alignmentleft
F(p, l)= \int_{p_0}^p \frac{dp}{\rho} -g \, \Delta z(l)
+ 0.5 \cdot j_m^2 \cdot \left[ 

\left(  \frac{f}{\rho^2} + \frac{f_0}{\rho_0^2}   \right)  
\cdot \frac{l}{ 2 \, d} +

\left(  \frac{1}{\rho^2} - \frac{1}{\rho_0^2}   \right)  
  \right]

 = 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(T,p) = f(%7B\rm Re%7D(T,p), \, \epsilon)

Darcy friction factor 

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

Reynolds number in Pipe Flow

LaTeX Math Inline
body\mu(T,p)

dynamic viscosity as function of fluid temperature 

LaTeX Math Inline
bodyT
 and pressure 
LaTeX Math Inline
bodyp

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

characteristic linear dimension of the pipe

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



Expand
titleDerivation


Panel
borderColorwheat
bgColormintcream
borderWidth7

See Pressure Profile in Stationary Quasi-Isothermal Homogenous Pipe Flow @model



The equation 

LaTeX Math Block Reference
anchorPressureProfile
 can also be written in the following form:

Pressure profile along the pipe


LaTeX Math Block
anchorF2
alignmentleft
F(p, l)= \int_{p_0}^p \frac{dp}{\rho} -g \, \Delta z(l)
+ 0.5 \cdot j_m^2 \cdot 
\left(  \frac{1}{\rho^2} - \frac{1}{\rho_0^2}   \right)  
+
\frac{16 \, l \, j_m}{d^2} \cdot
\left(  \frac{\mu \, \Phi}{\rho^2} + \frac{\mu_0 \, \Phi_0}{\rho_0^2}  \right)  
= 0


where

LaTeX Math Inline
body--uriencoded--\Phi = \frac%7B1%7D%7B64%7D \cdot %7B\rm Re%7D \cdot f

Reduced Friction Factor



See also

References


Show If
grouparax


Panel
bgColorpapayawhip
titleARAX