NU_CYL_EXT

Excel Usage

=NU_CYL_EXT(Re, Pr)
  • Re (float, required): Reynolds number (-)
  • Pr (float, required): Prandtl number (-)

Returns (float): Nusselt number (-)

Examples

Example 1: Example 7.3 (Incropera)

Inputs:

Re Pr
6071 0.7

Excel formula:

=NU_CYL_EXT(6071, 0.7)

Expected output:

40.63709

Example 2: Low Reynolds crossflow

Inputs:

Re Pr
100 0.7

Excel formula:

=NU_CYL_EXT(100, 0.7)

Expected output:

5.15613

Example 3: High Reynolds crossflow

Inputs:

Re Pr
1000000 0.7

Excel formula:

=NU_CYL_EXT(1000000, 0.7)

Expected output:

1226.72185

Example 4: Crossflow in water

Inputs:

Re Pr
1000 7

Excel formula:

=NU_CYL_EXT(1000, 7)

Expected output:

37.38043

Python Code

from ht.conv_external import Nu_cylinder_Churchill_Bernstein

def nu_cyl_ext(Re, Pr):
    """
    Nusselt number for crossflow over a single cylinder (Churchill-Bernstein).

    See: https://ht.readthedocs.io/en/latest/ht.conv_external.html#ht.conv_external.Nu_cylinder_Churchill_Bernstein

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

    Args:
        Re (float): Reynolds number (-)
        Pr (float): Prandtl number (-)

    Returns:
        float: Nusselt number (-)
    """
    try:
      Re = float(Re)
      Pr = float(Pr)

      if Re <= 0:
        return "Error: Re must be positive"
      if Pr <= 0:
        return "Error: Pr must be positive"

      return float(Nu_cylinder_Churchill_Bernstein(Re=Re, Pr=Pr))
    except Exception as e:
        return f"Error: {str(e)}"

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