CAVALLINI_SZ

This function evaluates the Cavallini-Smith-Zecchin condensation correlation for internal two-phase flow in tubes. It computes a two-phase heat transfer coefficient from an equivalent Reynolds number that blends gas and liquid flow contributions.

The Nusselt-number form is:

Nu = \frac{hD}{k_l} = 0.05 Re_{eq}^{0.8} Pr_l^{0.33}

where Re_{eq} is based on liquid and gas superficial flow terms with viscosity and density corrections. The output is a scalar heat transfer coefficient in W/m^2/K.

Excel Usage

=CAVALLINI_SZ(m, x, D, rhol, rhog, mul, mug, kl, Cpl)

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

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

Example 1: Example values from reference

Inputs:

m	x	D	rhol	rhog	mul	mug	kl	Cpl
1	0.4	0.3	800	2.5	0.00001	0.001	0.6	2300

Excel formula:

=CAVALLINI_SZ(1, 0.4, 0.3, 800, 2.5, 0.00001, 0.001, 0.6, 2300)

Expected output:

5578.22

Example 2: Low quality vapor fraction

Inputs:

m	x	D	rhol	rhog	mul	mug	kl	Cpl
0.5	0.1	0.05	900	6	0.0002	0.00002	0.12	2000

Excel formula:

=CAVALLINI_SZ(0.5, 0.1, 0.05, 900, 6, 0.0002, 0.00002, 0.12, 2000)

Expected output:

2273.43

Example 3: Mid quality vapor fraction

Inputs:

m	x	D	rhol	rhog	mul	mug	kl	Cpl
0.8	0.6	0.08	700	3	0.00015	0.00003	0.1	2400

Excel formula:

=CAVALLINI_SZ(0.8, 0.6, 0.08, 700, 3, 0.00015, 0.00003, 0.1, 2400)

Expected output:

5094.11

Example 4: Higher mass flow rate

Inputs:

m	x	D	rhol	rhog	mul	mug	kl	Cpl
2	0.7	0.12	650	4	0.00018	0.00004	0.11	2100

Excel formula:

=CAVALLINI_SZ(2, 0.7, 0.12, 650, 4, 0.00018, 0.00004, 0.11, 2100)

Expected output:

4647.2

Python Code

Show Code

from ht.condensation import Cavallini_Smith_Zecchin as ht_Cavallini_Smith_Zecchin

def Cavallini_SZ(m, x, D, rhol, rhog, mul, mug, kl, Cpl):
    """
    Calculate condensation heat transfer coefficient using the Cavallini-Smith-Zecchin correlation.

    See: https://ht.readthedocs.io/en/latest/ht.condensation.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 specific interval (-).
        D (float): Channel diameter (m).
        rhol (float): Liquid density (kg/m^3).
        rhog (float): Gas density (kg/m^3).
        mul (float): Liquid viscosity (Pa*s).
        mug (float): Gas viscosity (Pa*s).
        kl (float): Liquid thermal conductivity (W/m/K).
        Cpl (float): Liquid heat capacity at constant pressure (J/kg/K).

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

Online Calculator

m *

Mass flow rate (kg/s).

x *

Quality at the specific interval (-).

D *

Channel diameter (m).

rhol *

Liquid density (kg/m^3).

rhog *

Gas density (kg/m^3).

mul *

Liquid viscosity (Pa*s).

mug *

Gas viscosity (Pa*s).

kl *

Liquid thermal conductivity (W/m/K).

Cpl *

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