Power Calculation for Mixer

Power Equation for Impeller Mixing:

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

Power Number (N_p):

unitless

Density (ρ):

kg/m³

Rotational Speed (N):

rev/s

Impeller Diameter (D):

Power (P):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is Power Calculation for Mixer?

The power calculation for mixer determines the power required to drive an impeller in a fluid mixing system. This calculation is essential for designing efficient mixing equipment and ensuring proper motor sizing.

2. How Does the Calculator Work?

The calculator uses the power equation for impeller mixing:

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

Where:

\( P \) — Power (watts)
\( N_p \) — Power number (unitless)
\( \rho \) — Density (kg/m³)
\( N \) — Rotational speed (rev/s)
\( D \) — Impeller diameter (m)

Explanation: The power number represents the relationship between power consumption and fluid properties, while the equation accounts for the strong dependence on impeller diameter and rotational speed.

3. Importance of 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, fluid density, rotational speed in revolutions per second, and impeller diameter in meters. All values must be positive and non-zero.

5. Frequently Asked Questions (FAQ)

Q1: What is the power number (N_p)?
A: The power number is a dimensionless parameter that depends on impeller geometry, Reynolds number, and flow regime. Typical values range from 0.2 to 5.0.

Q2: How does impeller diameter affect power consumption?
A: Power consumption increases dramatically with impeller diameter (D⁵ relationship), making diameter the most influential parameter in the equation.

Q3: What are typical rotational speeds for mixing?
A: Rotational speeds vary widely depending on application, typically ranging from 1-10 rev/s for large industrial mixers to higher speeds for laboratory-scale equipment.

Q4: When is this equation most accurate?
A: This equation is most accurate for Newtonian fluids in turbulent flow conditions. For non-Newtonian fluids or transitional flow, additional corrections may be needed.

Q5: How does fluid viscosity affect power requirements?
A: Higher viscosity fluids generally require more power for mixing, which is reflected in the power number value for different flow regimes.