Agitator Design Calculation Xls

Agitator Power Equation:

\[ P = N_p \rho N^3 D^5 \]

Power Number (N_p):

Density (ρ):

kg/m³

Rotational Speed (N):

rev/s

Diameter (D):

Agitator Power (P):

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1. What Is The Agitator Power Equation?

The agitator power equation calculates the power required to rotate an agitator in a fluid. It is commonly used in chemical engineering, mixing processes, and industrial applications to determine motor sizing and energy requirements for agitation systems.

2. How Does The Calculator Work?

The calculator uses the agitator power equation:

\[ P = N_p \rho N^3 D^5 \]

Where:

\( P \) — Agitator power (watts)
\( N_p \) — Power number (dimensionless)
\( \rho \) — Fluid density (kg/m³)
\( N \) — Rotational speed (revolutions per second)
\( D \) — Impeller diameter (meters)

Explanation: The equation relates power consumption to fluid properties and agitator geometry, with the power number depending on agitator type and flow regime.

3. Importance Of Agitator Power Calculation

Details: Accurate power calculation is essential for proper motor selection, energy efficiency optimization, process design, and ensuring adequate mixing performance in industrial applications.

4. Using The Calculator

Tips: Enter power number based on agitator type, fluid density in kg/m³, rotational speed in rev/s, and impeller diameter in meters. All values must be positive and valid.

5. Frequently Asked Questions (FAQ)

Q1: What Are Typical Power Number Values?
A: Power numbers vary by agitator type: Rushton turbine (4-6), pitched blade turbine (1-2), marine propeller (0.3-1.0), anchor (0.2-1.0).

Q2: How Does Fluid Viscosity Affect Power?
A: Higher viscosity fluids require more power for agitation. Power number may change with Reynolds number in transitional flow regimes.

Q3: What Is The Reynolds Number For Agitators?
A: \( Re = \frac{\rho N D^2}{\mu} \), where μ is dynamic viscosity. Different flow regimes exist: laminar (Re < 10), transitional (10-10⁴), turbulent (Re > 10⁴).

Q4: Can This Equation Be Used For Non-Newtonian Fluids?
A: For non-Newtonian fluids, apparent viscosity must be used, and power correlations may differ significantly from Newtonian fluids.

Q5: How Important Is Baffling In Agitation?
A: Baffles prevent vortex formation and improve mixing efficiency. Unbaffled tanks require less power but have poor mixing characteristics.