LAMINAR_ENTRY_ST

Calculates the average Nusselt number for laminar internal flow in the thermal entry region using the Seider-Tate correlation. Optional bulk-to-wall viscosity correction can be applied when both viscosities are provided.

The correlation has the form:

Nu = 1.86\left(\frac{D}{L}Re\,Pr\right)^{1/3}\left(\frac{\mu}{\mu_w}\right)^{0.14}

and returns a dimensionless Nusselt number for use in convection calculations.

Excel Usage

=LAMINAR_ENTRY_ST(Re, Pr, L, Di, mu, mu_w)

Re (float, required): Reynolds number (-).
Pr (float, required): Prandtl number (-).
L (float, required): Pipe length (m).
Di (float, required): Pipe diameter (m).
mu (float, optional, default: null): Bulk viscosity (Pa*s).
mu_w (float, optional, default: null): Wall viscosity (Pa*s).

Returns (float): Laminar entry-region Nusselt number (-).

Example 1: Seider-Tate example

Inputs:

Re	Pr	L	Di
100000	1.1	5	0.5

Excel formula:

=LAMINAR_ENTRY_ST(100000, 1.1, 5, 0.5)

Expected output:

41.366

Example 2: Seider-Tate with viscosity correction

Inputs:

Re	Pr	L	Di	mu	mu_w
8000	5	1	0.05	0.003	0.004

Excel formula:

=LAMINAR_ENTRY_ST(8000, 5, 1, 0.05, 0.003, 0.004)

Expected output:

22.5094

Example 3: Mid Reynolds number

Inputs:

Re	Pr	L	Di
20000	0.9	2	0.1

Excel formula:

=LAMINAR_ENTRY_ST(20000, 0.9, 2, 0.1)

Expected output:

17.9581

Example 4: Short pipe length

Inputs:

Re	Pr	L	Di
5000	7	0.5	0.02

Excel formula:

=LAMINAR_ENTRY_ST(5000, 7, 0.5, 0.02)

Expected output:

20.8076

Python Code

Show Code

from ht.conv_two_phase import laminar_entry_Seider_Tate as ht_laminar_entry_Seider_Tate

def laminar_entry_ST(Re, Pr, L, Di, mu=None, mu_w=None):
    """
    Calculate laminar entry-region Nusselt number using Seider-Tate.

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

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

    Args:
        Re (float): Reynolds number (-).
        Pr (float): Prandtl number (-).
        L (float): Pipe length (m).
        Di (float): Pipe diameter (m).
        mu (float, optional): Bulk viscosity (Pa*s). Default is None.
        mu_w (float, optional): Wall viscosity (Pa*s). Default is None.

    Returns:
        float: Laminar entry-region Nusselt number (-).
    """
    try:
        return ht_laminar_entry_Seider_Tate(Re=Re, Pr=Pr, L=L, Di=Di, mu=mu, mu_w=mu_w)
    except Exception as e:
        return f"Error: {str(e)}"

Online Calculator

Re *

Reynolds number (-).

Pr *

Prandtl number (-).

L *

Pipe length (m).

Di *

Pipe diameter (m).

Bulk viscosity (Pa*s).

mu_w

Wall viscosity (Pa*s).