In fluid dynamics, the relationship between flow rate and pressure is fundamental for designing piping systems, HVAC units, and industrial machinery. This calculator specifically focuses on Dynamic Pressure, which represents the kinetic energy of a fluid in motion.
The Mathematical Formula
To find the dynamic pressure generated by a specific flow rate through a pipe, we follow these steps:
Calculate Velocity (v): v = Q / A, where Q is the flow rate in m³/s and A is the cross-sectional area of the pipe.
Calculate Area (A): A = π * (d/2)², where d is the internal diameter.
Calculate Dynamic Pressure (P): P = 0.5 * ρ * v², where ρ (rho) is the density of the fluid.
Why This Matters
When fluid moves through a pipe, its speed (velocity) creates pressure against surfaces. Higher flow rates in smaller diameters result in significantly higher velocities and, consequently, much higher dynamic pressures. Engineers use these calculations to ensure pipe walls can withstand the force and to size pumps correctly to overcome friction and system resistance.
Example Calculation
Suppose you have water (density 1000 kg/m³) flowing at 15 m³/h through a 50mm diameter pipe: