CTB_NU_ESDU_73031

This function calculates tube-bank Nusselt number for crossflow using the ESDU 73031-style correlation framework. It combines Reynolds and Prandtl scaling with finite-row and geometric effects through tube-row count and pitch ratios.

A wall-property correction can be included through Pr_{wall}, and bank inclination can be incorporated through the angle input.

Excel Usage

=CTB_NU_ESDU_73031(Re, Pr, tube_rows, pitch_parallel, pitch_normal, Pr_wall, angle)

Re (float, required): Reynolds number based on tube outer diameter (-).
Pr (float, required): Prandtl number at bulk conditions (-).
tube_rows (int, required): Number of tube rows per bundle (-).
pitch_parallel (float, required): Tube pitch parallel to flow (m).
pitch_normal (float, required): Tube pitch normal to flow (m).
Pr_wall (float, optional, default: null): Prandtl number at the wall temperature (-).
angle (float, optional, default: 90): Tube bank inclination angle relative to flow (deg).

Returns (float): Nusselt number for a tube bank, or an error message if invalid.

Example 1: Example staggered bundle

Inputs:

Re	Pr	tube_rows	pitch_parallel	pitch_normal
13200	0.71	8	0.09	0.05

Excel formula:

=CTB_NU_ESDU_73031(13200, 0.71, 8, 0.09, 0.05)

Expected output:

98.2563

Example 2: Inline bundle at low Reynolds number

Inputs:

Re	Pr	tube_rows	pitch_parallel	pitch_normal
200	1	6	0.06	0.08

Excel formula:

=CTB_NU_ESDU_73031(200, 1, 6, 0.06, 0.08)

Expected output:

8.36008

Example 3: Include wall Prandtl correction

Inputs:

Re	Pr	tube_rows	pitch_parallel	pitch_normal	Pr_wall
50000	0.9	12	0.08	0.05	1.1

Excel formula:

=CTB_NU_ESDU_73031(50000, 0.9, 12, 0.08, 0.05, 1.1)

Expected output:

240.875

Example 4: Inclined tube bank

Inputs:

Re	Pr	tube_rows	pitch_parallel	pitch_normal	angle
8000	1.2	9	0.07	0.05	75

Excel formula:

=CTB_NU_ESDU_73031(8000, 1.2, 9, 0.07, 0.05, 75)

Expected output:

84.4776

Python Code

Show Code

from ht.conv_tube_bank import Nu_ESDU_73031 as ht_Nu_ESDU_73031

def ctb_nu_esdu_73031(Re, Pr, tube_rows, pitch_parallel, pitch_normal, Pr_wall=None, angle=90):
    """
    Compute tube bank Nusselt number using the ESDU 73031 correlation.

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

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

    Args:
        Re (float): Reynolds number based on tube outer diameter (-).
        Pr (float): Prandtl number at bulk conditions (-).
        tube_rows (int): Number of tube rows per bundle (-).
        pitch_parallel (float): Tube pitch parallel to flow (m).
        pitch_normal (float): Tube pitch normal to flow (m).
        Pr_wall (float, optional): Prandtl number at the wall temperature (-). Default is None.
        angle (float, optional): Tube bank inclination angle relative to flow (deg). Default is 90.

    Returns:
        float: Nusselt number for a tube bank, or an error message if invalid.
    """
    try:
        return ht_Nu_ESDU_73031(
            Re=Re,
            Pr=Pr,
            tube_rows=tube_rows,
            pitch_parallel=pitch_parallel,
            pitch_normal=pitch_normal,
            Pr_wall=Pr_wall,
            angle=angle,
        )
    except Exception as e:
        return f"Error: {str(e)}"

Online Calculator

Re *

Reynolds number based on tube outer diameter (-).

Pr *

Prandtl number at bulk conditions (-).

tube_rows *

Number of tube rows per bundle (-).

pitch_parallel *

Tube pitch parallel to flow (m).

pitch_normal *

Tube pitch normal to flow (m).

Pr_wall

Prandtl number at the wall temperature (-).

angle

Tube bank inclination angle relative to flow (deg).