Pipe Calculations
|
Pipe Friction Loss Calculation
Friction losses of various pipes are calculated depending on the fluid temperature.
Explanation :
Reynolds Number (Formula \ref{Re}),
\begin{equation}\label{Re}
Re=\frac{vD}{\nu}=\frac{\rho vD}{\mu}
\end{equation}
\(Re\) is the Reynolds Number, \(v\) is the velocity [m/s], \(D\) is the inner diameter [m], \(\nu\) is the kinematic viscosity [m2/s]
\(\rho\) is the density [kg/m3], \(\mu\) is the dynamic viscosity [Pa.s]
Laminar flow in pipes \(Re<2500\) (Formula \ref{lam}),
\begin{equation}\label{lam}
f=\frac{64}{Re}
\end{equation}
The formula used is the Colebrook – White equation for turbulent flow (Re> 4000).(Formula \ref{eu_Colebrook})
\begin{equation}\label{eu_Colebrook}
\frac{1}{\sqrt{f }}=-2\log \left ( \frac{2.51}{Re\sqrt{f}}+\frac{\varepsilon /D}{3.71} \right )
\end{equation}
The friction loss occurring along the pipe is found from the Darcy-Weisbach equation.
\begin{equation}\label{darcy}
\displaystyle{h_{f}=f\displaystyle\frac{L}{D}\displaystyle\frac{v^{2}}{2g}} \qquad \text { mWG or }\qquad
\displaystyle{\Delta P=f\displaystyle\frac{L}{D}\displaystyle\frac{\rho v^{2}}{2} }\quad \text { Pa}
\end{equation}
Here, \( f\) is the dimensionless unit friction coefficient, \( Re\) is the dimensionless reynolt number,
\(\varepsilon\) is the Roughness[m], \(L\) is the pipe length[m], \(\rho\) is the density [kg/m3].
|