Engineering Toolbox Duct Calculator

Pressure Loss Equation:

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

Friction Factor (f):

dimensionless

Length (L):

Diameter (D):

Density (ρ):

kg/m³

Velocity (v):

m/s

Pressure Loss (ΔP):

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1. What is the Engineering Toolbox Duct Calculator?

The Engineering Toolbox Duct Calculator estimates pressure loss in duct systems using the Darcy-Weisbach equation. It provides accurate assessment of pressure drop in fluid flow systems, essential for HVAC and industrial duct design.

2. How Does the Calculator Work?

The calculator uses the pressure loss equation:

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

Where:

\( \Delta P \) — Pressure loss (Pa)
\( f \) — Friction factor (dimensionless)
\( L \) — Length of duct (m)
\( D \) — Diameter of duct (m)
\( \rho \) — Fluid density (kg/m³)
\( v \) — Fluid velocity (m/s)

Explanation: The equation calculates pressure drop due to friction in a duct system, accounting for fluid properties and duct geometry.

3. Importance of Pressure Loss Calculation

Details: Accurate pressure loss calculation is crucial for proper duct system design, fan selection, energy efficiency optimization, and ensuring adequate airflow in HVAC systems.

4. Using the Calculator

Tips: Enter friction factor, duct length, duct diameter, fluid density, and fluid velocity. All values must be positive and in appropriate units.

5. Frequently Asked Questions (FAQ)

Q1: How is friction factor determined?
A: Friction factor depends on Reynolds number and relative roughness. It can be found using Moody chart or calculated from empirical formulas.

Q2: What are typical friction factor values?
A: For smooth pipes, friction factor typically ranges from 0.008 to 0.03. For rough pipes, it can be higher depending on surface roughness.

Q3: When is this equation applicable?
A: The equation applies to steady, incompressible flow in circular ducts. For non-circular ducts, use hydraulic diameter.

Q4: Are there limitations to this equation?
A: The equation assumes fully developed turbulent flow and may need adjustments for laminar flow or complex duct geometries.

Q5: How does temperature affect the calculation?
A: Temperature affects fluid density and viscosity, which influence both Reynolds number and friction factor calculations.