rizer.models.nrp.isomass_2T_isobaric_reactor#

Attributes#

logger

Classes#

Isomass2TIsobaricReactor

Two-temperature 0D plasma reactor: constant mass, constant (total and partial) pressure.

Module Contents#

rizer.models.nrp.isomass_2T_isobaric_reactor.logger#

class rizer.models.nrp.isomass_2T_isobaric_reactor.Isomass2TIsobaricReactor(plasma: cantera.Solution, momentum_transfer_collision_frequencies_list: list[rizer.transport.collision_frequency.MomentumTransferCollisionFrequencyModel], electric_circuit: rizer.electrical_model.circuit.base_circuit.PlasmaVoltageCircuit | None = None, gap: float | None = None, initial_radius: float | None = None, mass: float | None = None, compute_chemistry: bool = True, compute_Te: bool = False, compute_Tg: bool = True, single_temperature: bool = False, T_wall: float | None = None, **kwargs)#

Bases: cantera.ExtensibleReactor

Two-temperature 0D plasma reactor: constant mass, constant (total and partial) pressure.

Driven by cantera.ReactorNet, mirroring the organization of Isomass2TVolumeReactor. Te is solved for, not prescribed.

This is a full replace_get_state/replace_update_state/replace_eval port, not an after_eval addition onto a stock IdealGasConstPressureReactor. Confirmed by testing a plain, unmodified ct.IdealGasConstPressureReactor on one of this project’s PlasmaPhase objects: its native energy equation unconditionally calls PlasmaPhase::intrinsicHeating() (native Joule heating, sigma = e n_e mu_e), which calls electronMobility(), which raises NotImplementedError for any electron-energy-distribution type other than "Boltzmann-two-term" – every mechanism in this repo (checked: simple.yaml, air_plasma_Laux2000.yaml, Goutier2025/CH4_to_C2H2.yaml) uses "isotropic", so the native energy equation cannot be used at all with these plasma phases, regardless of after_eval. A full replace bypasses the native eval() entirely, so this native-only code path never runs.

The following assumptions are made:

Constant mass plasma (no mass flow).
Homogeneous plasma (0D reactor).
Isobaric: the total pressure is constant, and (see Notes) the electron and heavy-species partial pressures are each assumed constant too, so the electron-/gas-energy balances below drop their pressure-derivative terms entirely.
Cylindrical geometry between two electrodes – only needed when compute_Te is enabled, to compute the electric field for Joule heating.
No heat loss to the surroundings unless T_wall is given (conductive loss to a wall at T_wall through the column radius, conductive_heat_loss()).
Multi-temperature ideal gas equation of state (Maxwellian distribution for each species, with different temperatures for electrons and heavy species).
Reflections of the generator voltage wave in the electric circuit are considered – only when compute_Te is enabled.
No surface chemistry.

Parameters:

plasma (cantera.Solution) – Cantera plasma object. Passed with clone=False, and stored as self.plasma (not read back via self.phase): self.phase re-wraps the underlying C++ phase fresh on every access, and that fresh wrapper does not carry the Python-side _enable_plasma flag, so plasma-only setters (.Te =) raise ThermoModelMethodError on it even though getters and generic ThermoPhase properties work fine. Storing the constructor argument directly sidesteps this; clone=False guarantees it shares the same underlying state.
momentum_transfer_collision_frequencies_list (list of MomentumTransferCollisionFrequencyModel) – List of momentum transfer collision frequency models for each species in the plasma object. Forwarded to MixtureCollisionFrequencies.
electric_circuit (PlasmaVoltageCircuit, optional) – Electric circuit object – any of TransmissionLineResistiveCircuit, TransmissionLineRCLoadCircuit, DirectResistiveCircuit, DirectRCLoadCircuit, GeneratorVoltageCircuit (see PlasmaVoltageCircuit). Required (and used to compute the Joule term) only if compute_Te.
gap (float, optional) – Gap between the two electrodes, in m. Used to compute the electric field from the plasma voltage. Required only if compute_Te.
initial_radius (float, optional) – Initial radius of the plasma, in m – only used to seed self.plasma_radius before the first RHS evaluation (the radius itself is then re-derived each step from the current density and mass, since there is no integrated volume state here). Required only if compute_Te.
mass (float, optional) – Mass of the plasma, in kg. Assumed constant. Used (with the current density) to derive the plasma volume/radius for the Joule term. Required only if compute_Te.
compute_chemistry (bool, optional) – Independently zero out a term’s RHS contribution without changing the state-vector layout (n_vars stays 2 + nsp regardless). compute_chemistry and compute_Tg default True; compute_Te defaults False (Te stays externally prescribed, matching this reactor’s original single-temperature behavior, unless explicitly enabled).
compute_Te (bool, optional) – Independently zero out a term’s RHS contribution without changing the state-vector layout (n_vars stays 2 + nsp regardless). compute_chemistry and compute_Tg default True; compute_Te defaults False (Te stays externally prescribed, matching this reactor’s original single-temperature behavior, unless explicitly enabled).
compute_Tg (bool, optional) – Independently zero out a term’s RHS contribution without changing the state-vector layout (n_vars stays 2 + nsp regardless). compute_chemistry and compute_Tg default True; compute_Te defaults False (Te stays externally prescribed, matching this reactor’s original single-temperature behavior, unless explicitly enabled).
single_temperature (bool, optional) – Tie Te to Tg (one temperature for the whole mixture): the electron-heavy exchange terms are internal to the mixture and drop out, and the gas-temperature equation becomes the mixture’s enthalpy balance (mixture cp including the electrons, every species’ enthalpy in the chemical term). dTe/dt = dTg/dt keeps the state vector layout unchanged. Cannot be combined with compute_Te. Default False.
T_wall (float, optional) – Wall temperature [K]. When given, the conductive wall loss conductive_heat_loss() at the live column radius (from mass, the density and gap, which are then both required) is subtracted from the gas-temperature equation. Default None: adiabatic.

Raises:

ValueError – If compute_Te=True and electric_circuit, gap, initial_radius or mass is not provided; if single_temperature=True and compute_Te=True or compute_Tg=False; or if T_wall is given without mass and gap.

Notes

Equations solved implies constant mass and homogeneous quantities only. The equations solved are based on [Aurora] and [Mitchner1973], adapted to constant pressure (enthalpy-based) rather than constant volume (internal-energy-based, see Isomass2TVolumeReactor).

Equation of state:

The equation of state chosen is the multi-temperature ideal gas law, like in [Chemkin]:

\[P = \sum_k [X_k] R T_k\]

where:

\(P\) is the pressure, in Pa,
\(X_k\) is the mole fraction of species \(k\),
\(R\) is the ideal gas constant, in J/mol/K,
\(T_k\) is the temperature of species \(k\), in K (\(T_e\) for electrons, \(T_g\) for heavy species).

Conservation of mass:

Since the system is assumed to be closed, the mass is constant:

\[\frac{dm}{dt} = 0\]

Isobaric assumption:

The total pressure \(P\) is held fixed. The electron and heavy-species partial pressures \(P_e\), \(P_g\) are each assumed constant too:

\[\frac{dP_e}{dt} = \frac{dP_g}{dt} = 0\]

which drops the pressure-derivative term from both energy equations below entirely (rather than solving for it) – see polytropic_volume_rate()’s own docstring note that a genuine isobaric closure needs “a different closure … enthalpy-based energy balance” than the polytropic volume-relaxation law used by Isomass2TVolumeReactor.

Balance equation for species mass fractions:

\[\frac{dY_k}{dt} = \frac{W_k \dot{\omega_k}}{\rho}\]

where:

\(Y_k\) the mass fraction of species \(k\),
\(W_k\) the molecular weight of species \(k\), in kg/kmol,
\(\omega_k\) the production rate of species \(k\), in kmol/m^3/s,
\(\rho\) the density, in kg/m^3.

Balance equation for the electron energy:

\[\rho Y_e c_{p, e} \frac{dT_e}{dt} = \vec{j} \cdot \vec{E} - \dot{\omega_e} M_e c_{p, e} T_e - \dot{Q}_{elas} - \dot{Q}_{inel}\]

where:

\(c_{p, e}\) the specific heat at constant pressure of the electrons, in J/kg/K,
\(Y_e\) the mass fraction of electrons,
\(T_e\) the electron temperature, in K,
\(\vec{j}\) the current density, in A/m^2,
\(\vec{E}\) the electric field, in V/m,
\(\omega_k\) the production rate of electron \(k\), in kmol/m^3/s,
\(M_e\) the molecular weight of the electron, in kg/kmol,
\(\dot{Q}_{elas}\) the heat production rate due to elastic collisions, in W/m^3,
\(\dot{Q}_{inel}\) the heat production rate due to inelastic collisions, in W/m^3.

Balance equation for the gas (heavy species) energy:

\[\rho \bar{c_p} \frac{dT_g}{dt} = - \sum_{k \neq e} W_k h_k \dot{\omega_k} + \dot{Q}_{elas} + \dot{Q}_{inel}\]

where:

\(\bar{c_p}=\sum_{k \neq e} c_{p, k} Y_k\) the mean specific heat at constant pressure of heavies species in the gas, in J/kg/K,
\(h_k\) the enthalpy of species \(k\), in J/kg.