MIXTURE_FLASH

This function performs a mixture flash calculation with the thermo package from component identifiers, composition, temperature, and pressure, then returns key bulk properties such as phase, vapor fraction, density, enthalpy, and entropy.

Input mole fractions are normalized before calculation so they sum to unity:

z_i^{*} = \frac{z_i}{\sum_j z_j}

The normalized composition and specified state variables are then used to solve for equilibrium state-dependent mixture properties.

Excel Usage

=MIXTURE_FLASH(compounds, fractions, temperature, pressure)
  • compounds (list[list], required): Range of chemical identifiers (names, CAS).
  • fractions (list[list], required): Range of mole fractions.
  • temperature (float, optional, default: 298.15): Temperature [K].
  • pressure (float, optional, default: 101325): Pressure [Pa].

Returns (list[list]): 2D array of property names and values.

Example 1: Ethanol-Water Mixture Flash

Inputs:

compounds fractions temperature pressure
Ethanol 0.5 350 101325
Water 0.5

Excel formula:

=MIXTURE_FLASH({"Ethanol";"Water"}, {0.5;0.5}, 350, 101325)

Expected output:

Property Value
Vapor Fraction 0
Phase l
Molar Volume 0.000039208
Enthalpy -37819.6
Entropy -97.7244
Density 817.228
Example 2: Pure Water at Standard Conditions

Inputs:

compounds fractions temperature pressure
Water 1 298.15 101325

Excel formula:

=MIXTURE_FLASH("Water", 1, 298.15, 101325)

Expected output:

Property Value
Vapor Fraction 0
Phase l
Molar Volume 0.0000180683
Enthalpy -43985.7
Entropy -118.728
Density 997.064
Example 3: Air (N2/O2) Mixture

Inputs:

compounds fractions temperature pressure
Nitrogen 0.79 300 101325
Oxygen 0.21

Excel formula:

=MIXTURE_FLASH({"Nitrogen";"Oxygen"}, {0.79;0.21}, 300, 101325)

Expected output:

Property Value
Vapor Fraction 1
Phase g
Molar Volume 0.0246172
Enthalpy 53.9815
Entropy 4.45377
Density 1.17196
Example 4: Methanol-Benzene Mixture

Inputs:

compounds fractions temperature pressure
Methanol 0.4 320 50000
Benzene 0.6

Excel formula:

=MIXTURE_FLASH({"Methanol";"Benzene"}, {0.4;0.6}, 320, 50000)

Expected output:

Property Value
Vapor Fraction 0
Phase l
Molar Volume 0.0000718494
Enthalpy -32604.2
Entropy -87.9393
Density 830.679

Python Code

Show Code 
from thermo import Mixture

def mixture_flash(compounds, fractions, temperature=298.15, pressure=101325):
    """
    Perform a flash calculation for a chemical mixture and return key properties.

    See: https://thermo.readthedocs.io/thermo.mixture.html

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

    Args:
        compounds (list[list]): Range of chemical identifiers (names, CAS).
        fractions (list[list]): Range of mole fractions.
        temperature (float, optional): Temperature [K]. Default is 298.15.
        pressure (float, optional): Pressure [Pa]. Default is 101325.

    Returns:
        list[list]: 2D array of property names and values.
    """
    def to_list(x):
        if isinstance(x, list):
            return [val for row in x for val in row if val is not None and val != ""]
        return [x] if x is not None else []

    try:
        ids = to_list(compounds)
        zs_raw = to_list(fractions)
        zs = [float(z) for z in zs_raw]

        if len(ids) != len(zs):
            return f"Error: Count mismatch: {len(ids)} compounds vs {len(zs)} fractions"

        total_z = sum(zs)
        if total_z == 0:
            return "Error: Sum of fractions must be greater than zero"
        zs = [z/total_z for z in zs]

        m = Mixture(ids, zs=zs, T=temperature, P=pressure)

        # Safer property extraction
        def get_prop(obj, attr):
            try:
                val = getattr(obj, attr)
                return float(val) if val is not None else 0.0
            except:
                return 0.0

        results = [
            ["Property", "Value"],
            ["Vapor Fraction", get_prop(m, 'VF')],
            ["Phase", str(m.phase)],
            ["Molar Volume", get_prop(m, 'Vm')],
            ["Enthalpy", get_prop(m, 'Hm')],
            ["Entropy", get_prop(m, 'Sm')],
            ["Density", get_prop(m, 'rho')]
        ]
        return results
    except Exception as e:
        return f"Error: {str(e)}"

Online Calculator

Range of chemical identifiers (names, CAS).
Range of mole fractions.
Temperature [K].
Pressure [Pa].