CTB_NU_ZUK_BEJAN

This function computes Nusselt number for crossflow over a tube bank using the Zukauskas-Bejan correlation family. It selects regime-dependent coefficient forms based on Reynolds number and arrangement implied by pitch geometry.

An optional wall-Prandtl correction term can be applied through Pr_{wall} when wall-property effects are needed.

Excel Usage

=CTB_NU_ZUK_BEJAN(Re, Pr, tube_rows, pitch_parallel, pitch_normal, Pr_wall)
  • 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 (-).

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

Example 1: Example tube bank case

Inputs:

Re Pr tube_rows pitch_parallel pitch_normal
10000 7 10 0.05 0.05

Excel formula:

=CTB_NU_ZUK_BEJAN(10000, 7, 10, 0.05, 0.05)

Expected output:

175.92

Example 2: Include wall Prandtl correction

Inputs:

Re Pr tube_rows pitch_parallel pitch_normal Pr_wall
5000 1.5 8 0.06 0.05 1.2

Excel formula:

=CTB_NU_ZUK_BEJAN(5000, 1.5, 8, 0.06, 0.05, 1.2)

Expected output:

66.0468

Example 3: Lower Reynolds number case

Inputs:

Re Pr tube_rows pitch_parallel pitch_normal
200 0.9 5 0.05 0.05

Excel formula:

=CTB_NU_ZUK_BEJAN(200, 0.9, 5, 0.05, 0.05)

Expected output:

0.607023

Example 4: High Reynolds number case

Inputs:

Re Pr tube_rows pitch_parallel pitch_normal
150000 0.7 20 0.07 0.05

Excel formula:

=CTB_NU_ZUK_BEJAN(150000, 0.7, 20, 0.07, 0.05)

Expected output:

367.056

Python Code

Show Code 
from ht.conv_tube_bank import Nu_Zukauskas_Bejan as ht_Nu_Zukauskas_Bejan

def ctb_nu_zuk_bejan(Re, Pr, tube_rows, pitch_parallel, pitch_normal, Pr_wall=None):
    """
    Compute tube bank Nusselt number using the Zukauskas-Bejan 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.

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

Online Calculator

Reynolds number based on tube outer diameter (-).
Prandtl number at bulk conditions (-).
Number of tube rows per bundle (-).
Tube pitch parallel to flow (m).
Tube pitch normal to flow (m).
Prandtl number at the wall temperature (-).