Total Pressure Loss Ducts Pipes

Overview

Engineering reference data for Total Pressure Loss Ducts Pipes in fluid mechanics.

Key Formulas

Reynolds Number

$Re = \frac{\rho v D}{\mu}$

Ratio of inertial to viscous forces — determines flow regime.

Bernoulli's Equation

$P + \frac{1}{2}\rho v^2 + \rho g h = \text{const}$

Conservation of energy for steady, inviscid, incompressible flow.

Continuity Equation

$A_1 v_1 = A_2 v_2$

Conservation of mass for incompressible flow.

Darcy-Weisbach

$\Delta P = f \frac{L}{D} \frac{\rho v^2}{2}$

Pressure drop due to friction in a pipe.

Variables

Total Head Loss for Serial Pipes

For pipe or duct systems connected in series, the total head loss is calculated by summing the losses across each individual segment. This accounts for both frictional (major) losses and component (minor) losses in each part of the system.

The formula for the total head loss in serial connected pipes is:

$h_{loss,serial} = \sum_{i=1}^{n} \left( \lambda_i \frac{l_i}{d_{h,i}} + \sum \xi_i \right) \frac{v_i^2}{2g}$

where:

• $n$ is the number of serial connected pipes or ducts
• $\lambda_i$ is the Darcy-Weisbach friction factor for the $i^{th}$ segment
• $l_i$ is the length of the $i^{th}$ segment
• $d_{h,i}$ is the hydraulic diameter of the $i^{th}$ segment
• $\sum \xi_i$ is the sum of minor loss coefficients for fittings and components in the $i^{th}$ segment
• $v_i$ is the flow velocity in the $i^{th}$ segment
• $g$ is the acceleration due to gravity

Note: Head loss values are based on the density of the flowing fluid. For conversions to other units, such as mm Water Column, refer to velocity pressure head calculations to ensure accuracy.

References

• Original Source