Streams & properties¶

The differentiable Stream pytree passed between units, and the property bridge that gives any stream a two-phase-aware enthalpy, entropy, density, and transport properties via fugacio.thermo.

Stream¶

stream ¶

Material streams: the data passed between flowsheet unit operations.

A Stream carries per-component molar flows together with temperature and pressure. It is registered as a JAX pytree (the flows, T and P are differentiable leaves while the component names are static metadata) so an entire flowsheet built from streams remains end-to-end differentiable. You can take a gradient of any downstream quantity with respect to a feed flow, temperature, or pressure.

Classes:

Name	Description
`Stream`	A process stream of fixed composition basis.

Stream `dataclass` ¶

Stream(
    n: Array,
    t: Array,
    p: Array,
    components: tuple[str, ...],
)

A process stream of fixed composition basis.

Attributes:

Name	Type	Description
`n`	`Array`	Per-component molar flow rates (mol/s), 1-D array aligned with `components`.
`t`	`Array`	Temperature (K).
`p`	`Array`	Pressure (Pa).
`components`	`tuple[str, ...]`	Canonical component names (static metadata).

Methods:

Name	Description
`from_fractions`	Build a stream from mole fractions `z` and a total molar `flow`.

total `property` ¶

total: Array

Total molar flow rate (mol/s).

z `property` ¶

z: Array

Mole fractions (the flow normalised to sum to one).

from_fractions `classmethod` ¶

from_fractions(
    components: tuple[str, ...],
    z: Array,
    flow: ArrayLike,
    t: ArrayLike,
    p: ArrayLike,
) -> Stream

Build a stream from mole fractions z and a total molar flow.

Stream properties¶

properties ¶

Stream property bridge: enthalpy, entropy, flows, and transport for a Stream.

Unit operations close material and energy balances, so they need a stream's enthalpy and entropy, not just its composition. This module resolves a stream's (static) component names to the array constants the fugacio.thermo kernels expect (caching that lookup, since names never change during a solve) and exposes the resulting molar and total-flow properties.

Enthalpy and entropy are two-phase aware: they run the equilibrium flash at the stream's (T, P) and blend the phase properties, so a subcooled liquid, a superheated vapour, and a flashing two-phase stream are all handled by the same call. Everything stays differentiable with respect to the stream's flows, temperature, and pressure (the component constants are not differentiated, which is exactly right: they are reference data, not decision variables).

Sizing-grade physical properties are surfaced too: phase densities and volumetric flows (liquid_density, vapor_volumetric_flow), viscosities, thermal conductivities, and surface tension, all evaluated at the stream's state through the curated correlations and mixture rules in fugacio.thermo. A stream-aware Souders-Brown helper (column_diameter_for) wires them straight into the equipment-sizing correlations of fugacio.sim.economics.

Functions:

Name	Description
`molar_enthalpy`	Molar enthalpy of the stream (J/mol), relative to the ideal-gas reference.
`molar_entropy`	Molar entropy of the stream (J/mol/K), relative to the ideal-gas reference.
`enthalpy_flow`	Total enthalpy flow of the stream (W = J/s).
`entropy_flow`	Total entropy flow of the stream (W/K).
`molar_mass`	Mole-fraction-averaged molar mass of the stream (g/mol).
`mass_flow`	Total mass flow of the stream (kg/s).
`liquid_density`	Saturated-liquid mass density at the stream's `T` and composition (kg/m^3).
`vapor_density`	Vapour mass density from the EOS at the stream's `(T, P)` (kg/m^3).
`liquid_volumetric_flow`	Volumetric flow if the stream is all liquid (m^3/s).
`vapor_volumetric_flow`	Volumetric flow if the stream is all vapour (m^3/s).
`liquid_viscosity`	Liquid-mixture viscosity at the stream's `T` (Pa*s), Grunberg-Nissan.
`vapor_viscosity`	Dilute-gas mixture viscosity at the stream's `T` (Pa*s), Wilke.
`liquid_thermal_conductivity`	Liquid-mixture thermal conductivity at the stream's `T` (W/m/K), DIPPR9H.
`vapor_thermal_conductivity`	Gas-mixture thermal conductivity at the stream's `T` (W/m/K), Wassiljewa.
`surface_tension`	Liquid-mixture surface tension at the stream's `T` (N/m).
`column_diameter_for`	Souders-Brown column/drum diameter sized from the actual stream states (m).

molar_enthalpy ¶

molar_enthalpy(
    stream: Stream,
    *,
    eos: CubicEOS = PR,
    kij: Array | None = None,
) -> Array

Molar enthalpy of the stream (J/mol), relative to the ideal-gas reference.

molar_entropy ¶

molar_entropy(
    stream: Stream,
    *,
    eos: CubicEOS = PR,
    kij: Array | None = None,
) -> Array

Molar entropy of the stream (J/mol/K), relative to the ideal-gas reference.

enthalpy_flow ¶

enthalpy_flow(
    stream: Stream,
    *,
    eos: CubicEOS = PR,
    kij: Array | None = None,
) -> Array

Total enthalpy flow of the stream (W = J/s).

entropy_flow ¶

entropy_flow(
    stream: Stream,
    *,
    eos: CubicEOS = PR,
    kij: Array | None = None,
) -> Array

Total entropy flow of the stream (W/K).

molar_mass ¶

molar_mass(stream: Stream) -> Array

Mole-fraction-averaged molar mass of the stream (g/mol).

mass_flow ¶

mass_flow(stream: Stream) -> Array

Total mass flow of the stream (kg/s).

liquid_density ¶

liquid_density(stream: Stream) -> Array

Saturated-liquid mass density at the stream's T and composition (kg/m^3).

vapor_density ¶

vapor_density(
    stream: Stream, *, eos: CubicEOS = PR
) -> Array

Vapour mass density from the EOS at the stream's (T, P) (kg/m^3).

liquid_volumetric_flow ¶

liquid_volumetric_flow(stream: Stream) -> Array

Volumetric flow if the stream is all liquid (m^3/s).

vapor_volumetric_flow ¶

vapor_volumetric_flow(
    stream: Stream, *, eos: CubicEOS = PR
) -> Array

Volumetric flow if the stream is all vapour (m^3/s).

liquid_viscosity ¶

liquid_viscosity(stream: Stream) -> Array

Liquid-mixture viscosity at the stream's T (Pa*s), Grunberg-Nissan.

vapor_viscosity ¶

vapor_viscosity(stream: Stream) -> Array

Dilute-gas mixture viscosity at the stream's T (Pa*s), Wilke.

liquid_thermal_conductivity ¶

liquid_thermal_conductivity(stream: Stream) -> Array

Liquid-mixture thermal conductivity at the stream's T (W/m/K), DIPPR9H.

vapor_thermal_conductivity ¶

vapor_thermal_conductivity(stream: Stream) -> Array

Gas-mixture thermal conductivity at the stream's T (W/m/K), Wassiljewa.

surface_tension ¶

surface_tension(stream: Stream) -> Array

Liquid-mixture surface tension at the stream's T (N/m).

column_diameter_for ¶

column_diameter_for(
    vapor: Stream,
    liquid: Stream | None = None,
    *,
    k_drum: ArrayLike = 0.07,
    flooding: ArrayLike = 0.8,
) -> Array

Souders-Brown column/drum diameter sized from the actual stream states (m).

The vapour density, molar mass, and flow come from vapor; the liquid density from liquid (defaulting to the vapour stream's composition at its own temperature, the saturated-liquid view of the same material, a sensible drum approximation).