1. What is the Agitator Power Equation?

The agitator power equation calculates the power required to operate a mixing impeller in a fluid. It is essential for proper agitator selection and motor sizing in industrial mixing applications.

2. How Does the Calculator Work?

The calculator uses the agitator power equation:

Where:

• \( P \) — Power requirement (W)
• \( N_p \) — Power number (dimensionless)
• \( \rho \) — Fluid density (kg/m³)
• \( N \) — Rotational speed (revolutions per second)
• \( D \) — Impeller diameter (m)

Explanation: The power number depends on impeller type, geometry, and flow regime (laminar or turbulent).

3. Importance of Power Calculation

Details: Accurate power calculation ensures proper motor selection, prevents under-mixing or over-mixing, and optimizes energy consumption in industrial processes.

4. Using the Calculator

Tips: Enter power number, fluid density in kg/m³, rotational speed in rps, and impeller diameter in meters. All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What is the power number (N_p)?
A: Power number is a dimensionless parameter that characterizes the resistance of an impeller to rotation in a fluid.

Q2: How do I determine the power number?
A: Power number depends on impeller type (Rushton turbine, propeller, etc.), Reynolds number, and geometric ratios.

Q3: What are typical power number values?
A: For turbulent flow: Rushton turbine ~5, propeller ~0.3-1.0, pitched blade turbine ~1.5-2.0.

Q4: Why use rps instead of rpm?
A: The equation requires rotational speed in revolutions per second (rps) for dimensional consistency.

Q5: Can this be used for non-Newtonian fluids?
A: For non-Newtonian fluids, apparent viscosity and modified Reynolds number must be used.