POWER_NUMBER

Excel Usage

=POWER_NUMBER(P, L, N, rho)
  • P (float, required): Power applied [W]
  • L (float, required): Characteristic length (typically agitator diameter) [m]
  • N (float, required): Rotational speed [revolutions/second]
  • rho (float, required): Density of fluid [kg/m^3]

Returns (float): Power number [-]

Examples

Example 1: Standard agitator case

Inputs:

P L N rho
180 0.01 2.5 800

Excel formula:

=POWER_NUMBER(180, 0.01, 2.5, 800)

Expected output:

144000000

Example 2: High power agitator

Inputs:

P L N rho
5000 0.05 10 1000

Excel formula:

=POWER_NUMBER(5000, 0.05, 10, 1000)

Expected output:

16000

Example 3: Low power case

Inputs:

P L N rho
10 0.005 1 900

Excel formula:

=POWER_NUMBER(10, 0.005, 1, 900)

Expected output:

3555555555.55556

Example 4: Dense fluid mixing

Inputs:

P L N rho
500 0.02 5 2000

Excel formula:

=POWER_NUMBER(500, 0.02, 5, 2000)

Expected output:

625000

Python Code

from fluids.core import Power_number as fluids_Power_number

def power_number(P, L, N, rho):
    """
    Calculate the Power number for an agitator.

    See: https://fluids.readthedocs.io/fluids.core.html#fluids.core.Power_number

    This example function is provided as-is without any representation of accuracy.

    Args:
        P (float): Power applied [W]
        L (float): Characteristic length (typically agitator diameter) [m]
        N (float): Rotational speed [revolutions/second]
        rho (float): Density of fluid [kg/m^3]

    Returns:
        float: Power number [-]
    """
    try:
      P_val = float(P)
      L_val = float(L)
      N_val = float(N)
      rho_val = float(rho)

      if L_val <= 0 or N_val <= 0 or rho_val <= 0:
        return "Error: Characteristic length, rotational speed, and density must be positive"

      if P_val < 0:
        return "Error: Power cannot be negative"

      result = fluids_Power_number(P_val, L_val, N_val, rho_val)
      return float(result)
    except Exception as e:
      return f"Error: {str(e)}"

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