Reactor Agitator Power Calculation

Agitator Power Equation:

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

Power Number (N_p):

unitless

Density (ρ):

kg/m³

Impeller Speed (N):

rev/s

Impeller Diameter (D):

Power Required (P):

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1. What is the Reactor Agitator Power Equation?

The reactor agitator power equation calculates the power required for agitation in chemical reactors using dimensionless power number. This is essential for designing efficient mixing systems in chemical processes.

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:

\( P \) — Power required (watts, W)
\( N_p \) — Power number (unitless)
\( \rho \) — Density of fluid (kg/m³)
\( N \) — Impeller rotational speed (rev/s)
\( D \) — Impeller diameter (m)

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

3. Importance of Agitator Power Calculation

Details: Accurate power calculation is crucial for selecting appropriate motors, ensuring efficient mixing, preventing equipment failure, and optimizing energy consumption in chemical processes.

4. Using the Calculator

Tips: Enter power number (typically 0.2-6 for different impellers), fluid density in kg/m³, impeller 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: Power number is a dimensionless parameter that characterizes the power consumption of an impeller. It depends on impeller type, geometry, and flow regime (laminar or turbulent).

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

Q3: What are typical power number values?
A: For common impellers: Rushton turbine ~5, pitched blade turbine ~1.5, marine propeller ~0.3, anchor ~0.3 (laminar flow).

Q4: Does this equation work for all flow regimes?
A: The equation is valid for turbulent flow. For transitional and laminar flow, power number becomes a function of Reynolds number.

Q5: What factors affect agitator power requirements?
A: Fluid viscosity, density, impeller type and size, rotational speed, baffle configuration, and vessel geometry all influence power consumption.