H_TWO_PHASE

Calculates a two-phase convective heat transfer coefficient for internal tube flow by dispatching to one of several supported empirical correlations. The selected method controls which property set is required and how flow behavior is modeled.

For all methods, the coefficient is interpreted through:

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

where Nu comes from the chosen correlation and may depend on mass quality, densities, viscosities, tube length, and void fraction.

Excel Usage

=H_TWO_PHASE(m, x, D, Cpl, kl, rhol, rhog, mul, mu_b, mu_w, mug, L, alpha, two_phase_method)

m (float, required): Mass flow rate (kg/s).
x (float, required): Quality at the tube interval (-).
D (float, required): Tube diameter (m).
Cpl (float, required): Liquid heat capacity at constant pressure (J/kg/K).
kl (float, required): Liquid thermal conductivity (W/m/K).
rhol (float, optional, default: null): Liquid density (kg/m^3).
rhog (float, optional, default: null): Gas density (kg/m^3).
mul (float, optional, default: null): Liquid viscosity (Pa*s).
mu_b (float, optional, default: null): Liquid viscosity at bulk conditions (Pa*s).
mu_w (float, optional, default: null): Liquid viscosity at wall temperature (Pa*s).
mug (float, optional, default: null): Gas viscosity (Pa*s).
L (float, optional, default: null): Tube length (m).
alpha (float, optional, default: null): Void fraction in the tube (-).
two_phase_method (str, optional, default: null): Correlation method name (-).

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

Example 1: Aggour method

Inputs:

m	x	D	alpha	rhol	Cpl	kl	mu_b	mu_w	L	two_phase_method
1	0.9	0.3	0.9	1000	2300	0.6	0.001	0.0012	5	Aggour

Excel formula:

=H_TWO_PHASE(1, 0.9, 0.3, 0.9, 1000, 2300, 0.6, 0.001, 0.0012, 5, "Aggour")

Expected output:

420.935

Example 2: Davis-David method

Inputs:

m	x	D	rhol	rhog	Cpl	kl	mul	two_phase_method
0.8	0.7	0.05	980	2.5	4180	0.6	0.001	Davis-David

Excel formula:

=H_TWO_PHASE(0.8, 0.7, 0.05, 980, 2.5, 4180, 0.6, 0.001, "Davis-David")

Expected output:

34257.4

Example 3: Groothuis-Hendal method

Inputs:

m	x	D	rhol	rhog	Cpl	kl	mug	mu_b	mu_w	two_phase_method
0.6	0.4	0.04	998	1.8	3900	0.55	0.00002	0.001	0.0011	Groothuis_Hendal

Excel formula:

=H_TWO_PHASE(0.6, 0.4, 0.04, 998, 1.8, 3900, 0.55, 0.00002, 0.001, 0.0011, "Groothuis_Hendal")

Expected output:

10305

Example 4: Hughmark method

Inputs:

m	x	D	alpha	Cpl	kl	L	mu_b	mu_w	two_phase_method
0.5	0.3	0.03	0.6	3600	0.52	1.5	0.0011	0.0013	Hughmark

Excel formula:

=H_TWO_PHASE(0.5, 0.3, 0.03, 0.6, 3600, 0.52, 1.5, 0.0011, 0.0013, "Hughmark")

Expected output:

746.114

Python Code

Show Code

from ht.conv_two_phase import h_two_phase as ht_h_two_phase

def h_two_phase(m, x, D, Cpl, kl, rhol=None, rhog=None, mul=None, mu_b=None, mu_w=None, mug=None, L=None, alpha=None, two_phase_method=None):
    """
    Calculate two-phase heat transfer coefficient using a selected 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).
        Cpl (float): Liquid heat capacity at constant pressure (J/kg/K).
        kl (float): Liquid thermal conductivity (W/m/K).
        rhol (float, optional): Liquid density (kg/m^3). Default is None.
        rhog (float, optional): Gas density (kg/m^3). Default is None.
        mul (float, optional): Liquid viscosity (Pa*s). Default is None.
        mu_b (float, optional): Liquid viscosity at bulk conditions (Pa*s). Default is None.
        mu_w (float, optional): Liquid viscosity at wall temperature (Pa*s). Default is None.
        mug (float, optional): Gas viscosity (Pa*s). Default is None.
        L (float, optional): Tube length (m). Default is None.
        alpha (float, optional): Void fraction in the tube (-). Default is None.
        two_phase_method (str, optional): Correlation method name (-). Valid options: Aggour, Davis-David, Elamvaluthi-Srinivas, Groothuis-Hendal, Hughmark, Knott, Kudirka-Grosh-McFadden, Martin-Sims, Ravipudi-Godbold. Default is None.

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

Online Calculator

m *

Mass flow rate (kg/s).

x *

Quality at the tube interval (-).

D *

Tube diameter (m).

Cpl *

Liquid heat capacity at constant pressure (J/kg/K).

kl *

Liquid thermal conductivity (W/m/K).

rhol

Liquid density (kg/m^3).

rhog

Gas density (kg/m^3).

mul

Liquid viscosity (Pa*s).

mu_b

Liquid viscosity at bulk conditions (Pa*s).

mu_w

Liquid viscosity at wall temperature (Pa*s).

mug

Gas viscosity (Pa*s).

Tube length (m).

alpha

Void fraction in the tube (-).

two_phase_method

Correlation method name (-).