NU_LAM_RECT_SHAN

This function computes the fully developed laminar Nusselt number for internal flow in a rectangular duct using the Shah–London polynomial correlation. The result depends on aspect ratio and assumes constant wall heat flux boundary conditions.

Excel Usage

=NU_LAM_RECT_SHAN(a_r)

• a_r (float, required): Aspect ratio of the channel (0 to 1) (-).

Returns (float): Nusselt number for laminar rectangular duct flow (-).

Example 1: Aspect ratio 0.7

Inputs:

a_r
0.7

Excel formula:

=NU_LAM_RECT_SHAN(0.7)

Expected output:

3.75176

Example 2: Square duct aspect ratio

Inputs:

a_r
1

Excel formula:

=NU_LAM_RECT_SHAN(1)

Expected output:

3.61022

Example 3: Low aspect ratio

Inputs:

a_r
0.2

Excel formula:

=NU_LAM_RECT_SHAN(0.2)

Expected output:

5.73825

Example 4: Mid aspect ratio

Inputs:

a_r
0.5

Excel formula:

=NU_LAM_RECT_SHAN(0.5)

Expected output:

4.12581

Python Code

Show Code

from ht.conv_internal import Nu_laminar_rectangular_Shan_London as ht_Nu_laminar_rectangular_Shan_London

def nu_lam_rect_shan(a_r):
    """
    Calculate the laminar Nusselt number for a rectangular duct.

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

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

    Args:
        a_r (float): Aspect ratio of the channel (0 to 1) (-).

    Returns:
        float: Nusselt number for laminar rectangular duct flow (-).
    """
    try:
        return ht_Nu_laminar_rectangular_Shan_London(a_r=a_r)
    except Exception as e:
        return f"Error: {str(e)}"

Online Calculator

a_r *

Aspect ratio of the channel (0 to 1) (-).