H_KINETIC

This function estimates condensation heat transfer using a kinetic-theory resistance model rather than a bulk convective correlation. It is useful when interfacial molecular transport contributes significantly to condensation resistance.

The model follows:

h = \left(\frac{2f}{2-f}\right)\left(\frac{MW}{1000\cdot 2\pi RT}\right)^{1/2}\left(\frac{H_{vap}^2 P\cdot MW}{1000\cdot RT^2}\right)

where f is an accommodation-style correction factor. The result is a scalar heat transfer coefficient in W/m^2/K.

Excel Usage

=H_KINETIC(T, P, MW, Hvap, f)

T (float, required): Vapor temperature (K).
P (float, required): Vapor pressure (Pa).
MW (float, required): Molecular weight (g/mol).
Hvap (float, required): Heat of vaporization (J/kg).
f (float, optional, default: 1): Correction factor (-).

Returns (float): Heat transfer coefficient (W/m^2/K).

Example 1: Example values from reference

Inputs:

T	P	MW	Hvap	f
300	100000	18.02	2441674	1

Excel formula:

=H_KINETIC(300, 100000, 18.02, 2441674, 1)

Expected output:

30788800

Example 2: Higher vapor pressure

Inputs:

T	P	MW	Hvap	f
320	200000	18.02	2300000	1

Excel formula:

=H_KINETIC(320, 200000, 18.02, 2300000, 1)

Expected output:

46497700

Example 3: Heavier molecule

Inputs:

T	P	MW	Hvap	f
350	150000	44.01	2000000	1

Excel formula:

=H_KINETIC(350, 150000, 44.01, 2000000, 1)

Expected output:

80444600

Example 4: Non unity correction factor

Inputs:

T	P	MW	Hvap	f
300	100000	18.02	2441674	0.9

Excel formula:

=H_KINETIC(300, 100000, 18.02, 2441674, 0.9)

Expected output:

25190900

Python Code

Show Code

from ht.condensation import h_kinetic as ht_h_kinetic

def h_kinetic(T, P, MW, Hvap, f=1):
    """
    Calculate kinetic theory condensation heat transfer coefficient.

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

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

    Args:
        T (float): Vapor temperature (K).
        P (float): Vapor pressure (Pa).
        MW (float): Molecular weight (g/mol).
        Hvap (float): Heat of vaporization (J/kg).
        f (float, optional): Correction factor (-). Default is 1.

    Returns:
        float: Heat transfer coefficient (W/m^2/K).
    """
    try:
        result = ht_h_kinetic(T=T, P=P, MW=MW, Hvap=Hvap, f=f)
        return result
    except Exception as e:
        return f"Error: {str(e)}"

Online Calculator

T *

Vapor temperature (K).

P *

Vapor pressure (Pa).

MW *

Molecular weight (g/mol).

Hvap *

Heat of vaporization (J/kg).

Correction factor (-).