Agitator Impeller Design Calculations

Agitator Power Equation:

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

Power Number (N_p):

Density (ρ):

kg/m³

Rotational Speed (N):

rps

Impeller Diameter (D):

Agitator Power (P):

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1. What is the Agitator Power Equation?

The agitator power equation calculates the power required for impeller operation in fluid mixing applications. It is essential for designing efficient mixing systems in chemical, pharmaceutical, and food processing industries.

2. How Does the Calculator Work?

The calculator uses the agitator power equation:

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

Where:

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

Explanation: The equation relates power consumption to impeller geometry, rotational speed, and fluid properties through the power number correlation.

3. Importance of Agitator Power Calculation

Details: Accurate power calculation is crucial for proper motor selection, energy efficiency optimization, and ensuring adequate mixing performance in industrial processes.

4. Using the Calculator

Tips: Enter power number (typically 0.2-5 for common impellers), fluid density in kg/m³, rotational speed in revolutions per second, and impeller diameter in meters. All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What is the power number (N_p)?
A: The power number is a dimensionless parameter that characterizes the power consumption of an impeller type and depends on impeller geometry and flow regime.

Q2: How do I determine the power number for my impeller?
A: Power numbers are typically obtained from manufacturer specifications, literature correlations, or experimental data for specific impeller types.

Q3: What are typical power number ranges?
A: Radial flow impellers: 3-5, axial flow impellers: 0.2-1.0, depending on Reynolds number and impeller design.

Q4: Does fluid viscosity affect the calculation?
A: Yes, viscosity affects the power number, especially in laminar and transitional flow regimes. The power number becomes constant only in fully turbulent flow.

Q5: What are common applications of this calculation?
A: Chemical reactors, bioreactors, mixing tanks, wastewater treatment, food processing, and pharmaceutical manufacturing.