NU_HPLATE_ROHSENOW

This function computes free-convection Nusselt number for a horizontal isothermal plate using the Rohsenow-family correlation in ht. It supports buoyancy-assisted and buoyancy-opposed orientations.

Inputs are interpreted through Rayleigh-number scaling:

Ra = Gr\,Pr

and the output is a dimensionless Nusselt number referenced to plate length.

Excel Usage

=NU_HPLATE_ROHSENOW(Pr, Gr, buoyancy)

Pr (float, required): Prandtl number of the fluid (dimensionless).
Gr (float, required): Grashof number for the plate (dimensionless).
buoyancy (bool, optional, default: true): Whether buoyancy assists free convection (dimensionless).

Returns (float): Nusselt number based on plate length (dimensionless).

Example 1: Rohsenow hot plate example

Inputs:

Pr	Gr	buoyancy
5.54	321000000	true

Excel formula:

=NU_HPLATE_ROHSENOW(5.54, 321000000, TRUE)

Expected output:

175.911

Example 2: Rohsenow cold plate example

Inputs:

Pr	Gr	buoyancy
5.54	321000000	false

Excel formula:

=NU_HPLATE_ROHSENOW(5.54, 321000000, FALSE)

Expected output:

35.958

Example 3: Rohsenow mid Grashof

Inputs:

Pr	Gr	buoyancy
0.9	2000000	true

Excel formula:

=NU_HPLATE_ROHSENOW(0.9, 2000000, TRUE)

Expected output:

17.1376

Example 4: Rohsenow low Grashof

Inputs:

Pr	Gr	buoyancy
0.7	200000	false

Excel formula:

=NU_HPLATE_ROHSENOW(0.7, 200000, FALSE)

Expected output:

5.43349

Python Code

Show Code

from ht.conv_free_immersed import Nu_horizontal_plate_Rohsenow as ht_Nu_horizontal_plate_Rohsenow

def Nu_hplate_Rohsenow(Pr, Gr, buoyancy=True):
    """
    Calculate the Nusselt number for a horizontal plate using Rohsenow.

    See: https://ht.readthedocs.io/en/latest/ht.conv_free_immersed.html

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

    Args:
        Pr (float): Prandtl number of the fluid (dimensionless).
        Gr (float): Grashof number for the plate (dimensionless).
        buoyancy (bool, optional): Whether buoyancy assists free convection (dimensionless). Default is True.

    Returns:
        float: Nusselt number based on plate length (dimensionless).
    """
    try:
        result = ht_Nu_horizontal_plate_Rohsenow(Pr, Gr, buoyancy=buoyancy)
        if result is None:
            return "Error: Result is None"
        return float(result)
    except Exception as e:
        return f"Error: {str(e)}"

Online Calculator

Pr *

Prandtl number of the fluid (dimensionless).

Gr *

Grashof number for the plate (dimensionless).

buoyancy

Whether buoyancy assists free convection (dimensionless).