DAVIS_DAVID

Computes the two-phase convective heat transfer coefficient inside a tube using the Davis-David correlation for liquid-gas mixtures. The method combines density ratio, mixture flow effects, and liquid thermal properties to estimate convection intensity.

The heat transfer coefficient follows the standard relation:

h = \frac{Nu\,k_l}{D}

with Nu evaluated from the Davis-David empirical expression based on mass flow, quality, and fluid properties.

Excel Usage

=DAVIS_DAVID(m, x, D, rhol, rhog, Cpl, kl, mul)
  • m (float, required): Mass flow rate (kg/s).
  • x (float, required): Quality at the tube interval (-).
  • D (float, required): Tube diameter (m).
  • rhol (float, required): Liquid density (kg/m^3).
  • rhog (float, required): Gas density (kg/m^3).
  • Cpl (float, required): Liquid heat capacity at constant pressure (J/kg/K).
  • kl (float, required): Liquid thermal conductivity (W/m/K).
  • mul (float, required): Liquid viscosity (Pa*s).

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

Example 1: Davis-David example

Inputs:

m x D rhol rhog Cpl kl mul
1 0.9 0.3 1000 2.5 2300 0.6 0.001

Excel formula:

=DAVIS_DAVID(1, 0.9, 0.3, 1000, 2.5, 2300, 0.6, 0.001)

Expected output:

1437.33

Example 2: Lower quality flow

Inputs:

m x D rhol rhog Cpl kl mul
0.8 0.2 0.05 980 3 4100 0.58 0.0012

Excel formula:

=DAVIS_DAVID(0.8, 0.2, 0.05, 980, 3, 4100, 0.58, 0.0012)

Expected output:

9768.73

Example 3: Small diameter tube

Inputs:

m x D rhol rhog Cpl kl mul
0.4 0.7 0.02 1005 1.8 3900 0.62 0.0009

Excel formula:

=DAVIS_DAVID(0.4, 0.7, 0.02, 1005, 1.8, 3900, 0.62, 0.0009)

Expected output:

119680

Example 4: Higher liquid viscosity

Inputs:

m x D rhol rhog Cpl kl mul
1.2 0.6 0.08 900 2 3500 0.5 0.003

Excel formula:

=DAVIS_DAVID(1.2, 0.6, 0.08, 900, 2, 3500, 0.5, 0.003)

Expected output:

9166.13

Python Code

Show Code 
from ht.conv_two_phase import Davis_David as ht_Davis_David

def Davis_David(m, x, D, rhol, rhog, Cpl, kl, mul):
    """
    Calculate two-phase heat transfer coefficient using the Davis-David correlation.

    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:
        m (float): Mass flow rate (kg/s).
        x (float): Quality at the tube interval (-).
        D (float): Tube diameter (m).
        rhol (float): Liquid density (kg/m^3).
        rhog (float): Gas density (kg/m^3).
        Cpl (float): Liquid heat capacity at constant pressure (J/kg/K).
        kl (float): Liquid thermal conductivity (W/m/K).
        mul (float): Liquid viscosity (Pa*s).

    Returns:
        float: Heat transfer coefficient (W/m^2/K).
    """
    try:
        return ht_Davis_David(
            m=m,
            x=x,
            D=D,
            rhol=rhol,
            rhog=rhog,
            Cpl=Cpl,
            kl=kl,
            mul=mul,
        )
    except Exception as e:
        return f"Error: {str(e)}"

Online Calculator

Mass flow rate (kg/s).
Quality at the tube interval (-).
Tube diameter (m).
Liquid density (kg/m^3).
Gas density (kg/m^3).
Liquid heat capacity at constant pressure (J/kg/K).
Liquid thermal conductivity (W/m/K).
Liquid viscosity (Pa*s).