Pipe Flow Rate Calculator
Calculate volumetric flow rate, average velocity, mass flow rate, and Reynolds number for fluid flow through a circular pipe.
Results will appear here.
Formulas Used
Cross-sectional Area:
A = π × (D/2)²
Volumetric Flow Rate (Continuity Equation):
Q = A × v
Mass Flow Rate:
ṁ = ρ × Q
Reynolds Number:
Re = (ρ × v × D) / μ
Where: D = inner diameter (m), v = average velocity (m/s), ρ = fluid density (kg/m³), μ = dynamic viscosity (Pa·s)
Assumptions & References
- Pipe cross-section is assumed to be perfectly circular.
- Flow velocity entered is the average (mean) velocity across the cross-section.
- Fluid is assumed incompressible and Newtonian.
- Flow regime thresholds: Re < 2300 → Laminar; 2300 ≤ Re ≤ 4000 → Transitional; Re > 4000 → Turbulent (Moody, 1944).
- Default values correspond to water at ~20 °C (ρ = 1000 kg/m³, μ = 0.001 Pa·s).
- Reference: White, F.M. Fluid Mechanics, 8th ed., McGraw-Hill, 2016.