Agitator Power Calculation

Agitator Power Equation:

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

Density (ρ):

kg/m³

Power Number (Np):

Rotational Speed (N):

rpm

Diameter (D):

Agitator Power (P):

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1. What is Agitator Power Calculation?

Agitator power calculation determines the power required to operate an agitator or mixer in fluid systems. It is essential for proper equipment selection, energy efficiency, and process optimization in various industrial applications.

2. How Does the Calculator Work?

The calculator uses the agitator power equation:

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

Where:

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

Explanation: The equation shows that power consumption is proportional to fluid density, power number (which depends on impeller type and flow regime), and strongly influenced by rotational speed and impeller diameter.

3. Importance of Agitator Power Calculation

Details: Accurate power calculation ensures proper motor sizing, prevents equipment failure, optimizes energy consumption, and maintains process efficiency in mixing operations across chemical, pharmaceutical, food, and water treatment industries.

4. Using the Calculator

Tips: Enter fluid density in kg/m³, power number (typically 0.2-6 for different impeller types), rotational speed in rpm, and impeller diameter in meters. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the power number (Np)?
A: The power number is a dimensionless parameter that depends on impeller geometry, Reynolds number, and flow regime. It represents the relationship between power consumption and operating conditions.

Q2: How does impeller diameter affect power consumption?
A: Power consumption increases with the fifth power of impeller diameter (D⁵), making diameter the most significant factor in power requirements.

Q3: What are typical power number values?
A: Radial flow impellers (Rushton turbine): 4-6; Axial flow impellers (marine propeller): 0.2-0.5; High-efficiency impellers: 0.3-1.0.

Q4: When is this equation most accurate?
A: The equation is most accurate in turbulent flow conditions (Re > 10,000) where the power number becomes constant.

Q5: How does fluid viscosity affect power calculation?
A: In laminar and transitional flow regimes, power number depends on Reynolds number, requiring correction factors for accurate calculations.