NU_COIL_XIN_EBADIAN

This function computes the Nusselt number for natural convection around a helical coil using the Xin-Ebadian correlation from the ht library. It supports both vertical and horizontal coil orientation and uses fluid properties at film conditions.

The correlation is represented as a power-law in Rayleigh number:

Nu = C\,(Gr\,Pr)^n

where the coefficient C depends on coil orientation.

Excel Usage

=NU_COIL_XIN_EBADIAN(Pr, Gr, horizontal)

Pr (float, required): Prandtl number at film temperature (dimensionless).
Gr (float, required): Grashof number based on coil outer diameter (dimensionless).
horizontal (bool, optional, default: false): Whether the coil is horizontal (dimensionless).

Returns (float): Nusselt number based on coil outer diameter (dimensionless).

Example 1: Vertical coil example

Inputs:

Pr	Gr	horizontal
0.7	20000	false

Excel formula:

=NU_COIL_XIN_EBADIAN(0.7, 20000, FALSE)

Expected output:

4.75569

Example 2: Horizontal coil example

Inputs:

Pr	Gr	horizontal
0.7	20000	true

Excel formula:

=NU_COIL_XIN_EBADIAN(0.7, 20000, TRUE)

Expected output:

5.21486

Example 3: Vertical coil mid range

Inputs:

Pr	Gr	horizontal
1.1	80000	false

Excel formula:

=NU_COIL_XIN_EBADIAN(1.1, 80000, FALSE)

Expected output:

8.14951

Example 4: Horizontal coil low Prandtl

Inputs:

Pr	Gr	horizontal
0.2	60000	true

Excel formula:

=NU_COIL_XIN_EBADIAN(0.2, 60000, TRUE)

Expected output:

4.98456

Python Code

Show Code

from ht.conv_free_immersed import Nu_coil_Xin_Ebadian as ht_Nu_coil_Xin_Ebadian

def Nu_coil_Xin_Ebadian(Pr, Gr, horizontal=False):
    """
    Calculate the Nusselt number for natural convection around a helical coil.

    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 at film temperature (dimensionless).
        Gr (float): Grashof number based on coil outer diameter (dimensionless).
        horizontal (bool, optional): Whether the coil is horizontal (dimensionless). Default is False.

    Returns:
        float: Nusselt number based on coil outer diameter (dimensionless).
    """
    try:
        result = ht_Nu_coil_Xin_Ebadian(Pr, Gr, horizontal=horizontal)
        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 at film temperature (dimensionless).

Gr *

Grashof number based on coil outer diameter (dimensionless).

horizontal

Whether the coil is horizontal (dimensionless).