NU_CONV_INTERNAL

This function selects and applies an internal-convection correlation to compute pipe-flow Nusselt number from Reynolds and Prandtl numbers, with optional roughness, entry-length, friction-factor, and explicit method controls. It serves as a high-level dispatcher for laminar and turbulent regimes.

Excel Usage

=NU_CONV_INTERNAL(Re, Pr, eD, Di, x, fd, Method)

Re (float, required): Reynolds number (-).
Pr (float, required): Prandtl number (-).
eD (float, optional, default: 0): Relative roughness (-).
Di (float, optional, default: null): Inside diameter of the pipe (m).
x (float, optional, default: null): Axial distance from the inlet (m).
fd (float, optional, default: null): Darcy friction factor (-).
Method (str, optional, default: null): Correlation method name (-).

Returns (float): Nusselt number for internal pipe flow (-).

Example 1: Turbulent flow default method

Inputs:

Re	Pr
100000	0.7

Excel formula:

=NU_CONV_INTERNAL(100000, 0.7)

Expected output:

183.711

Example 2: Laminar entry length case

Inputs:

Re	Pr	x	Di
100	0.7	0.01	0.1

Excel formula:

=NU_CONV_INTERNAL(100, 0.7, 0.01, 0.1)

Expected output:

14.918

Example 3: Rough pipe with higher Prandtl number

Inputs:

Re	Pr	eD
50000	2	0.001

Excel formula:

=NU_CONV_INTERNAL(50000, 2, 0.001)

Expected output:

209.914

Example 4: Turbulent entry length case

Inputs:

Re	Pr	Di	x
200000	1	0.05	0.5

Excel formula:

=NU_CONV_INTERNAL(200000, 1, 0.05, 0.5)

Expected output:

417.218

Python Code

Show Code

from ht.conv_internal import Nu_conv_internal as ht_Nu_conv_internal

def nu_conv_internal(Re, Pr, eD=0, Di=None, x=None, fd=None, Method=None):
    """
    Compute the Nusselt number for internal pipe convection.

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

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

    Args:
        Re (float): Reynolds number (-).
        Pr (float): Prandtl number (-).
        eD (float, optional): Relative roughness (-). Default is 0.
        Di (float, optional): Inside diameter of the pipe (m). Default is None.
        x (float, optional): Axial distance from the inlet (m). Default is None.
        fd (float, optional): Darcy friction factor (-). Default is None.
        Method (str, optional): Correlation method name (-). Default is None.

    Returns:
        float: Nusselt number for internal pipe flow (-).
    """
    try:
        return ht_Nu_conv_internal(
            Re=Re,
            Pr=Pr,
            eD=eD,
            Di=Di,
            x=x,
            fd=fd,
            Method=Method,
        )
    except Exception as e:
        return f"Error: {str(e)}"

Online Calculator

Re *

Reynolds number (-).

Pr *

Prandtl number (-).

Relative roughness (-).

Inside diameter of the pipe (m).

Axial distance from the inlet (m).

Darcy friction factor (-).

Method

Correlation method name (-).