engine.pipeline.config_schemas.StabilityConfig Class Reference

Inheritance diagram for engine.pipeline.config_schemas.StabilityConfig:

Collaboration diagram for engine.pipeline.config_schemas.StabilityConfig:

Static Public Attributes
float	n_interaction
float	chi_acoustic
Optional	mach_nozzle_entrance
float	damping_injector_frac
float	damping_twophase_frac
float	droplet_loading
float	acoustic_gate_alpha_offset
Literal	acoustic_gate
Literal	time_lag_model
Literal	convection_model
float	mixing_lag_fraction
bool	regulator_enabled = Field(default=True, description="Model the dome regulator upstream of each tank in the chug loop.")
float	regulator_corner_hz = Field(default=3.0, gt=0, description="Regulator response corner frequency [Hz].")
Optional	chug_band_mixing_lag_fraction_min
Optional	chug_band_mixing_lag_fraction_max
float	regulator_Z_hf
float	regulator_max_excursion_psi

Detailed Description

Inputs to the combustion / feed stability model that belong to neither the propellant
(``fluids``) nor the plumbing (``feed_system``): the combustion-response calibration, the
nozzle-entrance Mach the acoustic damping uses, the acoustic damping coefficients, and the
dome-regulator dynamics. A ``None`` here means "derive it" and the derivation is recorded in
the assumptions registry (rich report -> assumptions.fallbacks_used), never substituted silently.

Definition at line 1216 of file config_schemas.py.

Member Data Documentation

acoustic_gate

Literal engine.pipeline.config_schemas.StabilityConfig.acoustic_gate

static

Initial value:

=  Field(
        default="report_only",
        description=(
            "Which acoustic (HF) margin reaches the stability gate. 'report_only': none -- the modes, "
            "damping budget and margins are reported but gate nothing, because the injector-face and "
            "two-phase damping are uncalibrated and omega*tau_sens spans many periods of 2*pi (Harrje & "
            "Reardon SP-194 rate HF stability by test). 'nominal_phase': damping/driving at the model's "
            "tau_sens. 'worst_phase': damping/driving at omega*tau = pi (Crocco's n_min/n)."
        ),
    )

Definition at line 1255 of file config_schemas.py.

acoustic_gate_alpha_offset

float engine.pipeline.config_schemas.StabilityConfig.acoustic_gate_alpha_offset

static

Initial value:

=  Field(
        default=350.0, ge=0,
        description=(
            "UNUSED. Was an allowance that let a mode growing at up to this rate [1/s] pass the old "
            "tanh-remapped acoustic gate. The acoustic margin is now damping/driving (1 = neutral) and "
            "stability.acoustic_gate decides whether it gates. Kept so older configs still load."
        ),
    )

Definition at line 1247 of file config_schemas.py.

chi_acoustic

float engine.pipeline.config_schemas.StabilityConfig.chi_acoustic

static

Initial value:

=  Field(
        default=0.15, gt=0, le=1,
        description="Sensitive-lag fraction chi: tau_sens = chi * tau_vap for the acoustic n-tau driving.",
    )

Definition at line 1227 of file config_schemas.py.

chug_band_mixing_lag_fraction_max

Optional engine.pipeline.config_schemas.StabilityConfig.chug_band_mixing_lag_fraction_max

static

Initial value:

=  Field(
        default=1.0, ge=0.0, le=3.0,
        description="High end of the chug gate's mixing-lag fraction band (see the _min field).",
    )

Definition at line 1303 of file config_schemas.py.

chug_band_mixing_lag_fraction_min

Optional engine.pipeline.config_schemas.StabilityConfig.chug_band_mixing_lag_fraction_min

static

Initial value:

=  Field(
        default=0.0, ge=0.0, le=3.0,
        description=(
            "Low end of the mixing-lag fraction band the chug gate must hold over. The fraction's only "
            "source is Leonardi 2017's GH2/LOX coaxial rig (0.5); nothing measures it for this "
            "propellant or injector, so the gate takes the lowest gain margin over [min, max]. Set both "
            "ends null to gate on mixing_lag_fraction alone once it is measured. leonardi_dtl only."
        ),
    )

Definition at line 1294 of file config_schemas.py.

convection_model

Literal engine.pipeline.config_schemas.StabilityConfig.convection_model

static

Initial value:

=  Field(
        default="none",
        description=(
            "Convective speed-up applied to the droplet lifetime. Default 'none': the Leonardi eq. 9 "
            "evaporation constant is already calibrated against real chamber data, and applying "
            "eq. 8 on top of it triples the chug-frequency error against the reference experiment."
        ),
    )

Definition at line 1275 of file config_schemas.py.

damping_injector_frac

float engine.pipeline.config_schemas.StabilityConfig.damping_injector_frac

static

Initial value:

=  Field(
        default=0.02, ge=0,
        description="Injector-face acoustic damping as a fraction of pi*f [-]. ASSUMED, uncalibrated (no source); calibrate against a cold ring-down test (T7).",
    )

Definition at line 1235 of file config_schemas.py.

damping_twophase_frac

float engine.pipeline.config_schemas.StabilityConfig.damping_twophase_frac

static

Initial value:

=  Field(
        default=0.03, ge=0,
        description="Two-phase (droplet) acoustic damping as a fraction of pi*f*droplet_loading [-]. ASSUMED, uncalibrated (no source).",
    )

Definition at line 1239 of file config_schemas.py.

droplet_loading

float engine.pipeline.config_schemas.StabilityConfig.droplet_loading

static

Initial value:

=  Field(
        default=1.0, ge=0,
        description="Relative liquid loading near the injector face for the two-phase damping term [-].",
    )

Definition at line 1243 of file config_schemas.py.

mach_nozzle_entrance

Optional engine.pipeline.config_schemas.StabilityConfig.mach_nozzle_entrance

static

Initial value:

=  Field(
        default=None, gt=0, lt=1,
        description="Mean Mach at the nozzle entrance (sets nozzle damping). None = solve it from the contraction ratio (isentropic, subsonic).",
    )

Definition at line 1231 of file config_schemas.py.

mixing_lag_fraction

float engine.pipeline.config_schemas.StabilityConfig.mixing_lag_fraction

static

Initial value:

=  Field(
        default=0.5, ge=0.0, le=3.0,
        description=(
            "Mixing lag as a fraction of the rate-limiting vaporization lag, shared by every stream "
            "(a gaseous propellant carries this and nothing else). Default 0.5 is Leonardi's own "
            "calibration for the validation engine: tau_mix = 2.2 ms at tau_vap = 4.4 ms. Set 0 to "
            "drop the mixing lag entirely."
        ),
    )

Definition at line 1283 of file config_schemas.py.

n_interaction

float engine.pipeline.config_schemas.StabilityConfig.n_interaction

static

Initial value:

=  Field(
        default=0.5, gt=0,
        description="Crocco interaction index n (calibration range 0.3-0.6). The forward-mode slider overrides it per run.",
    )

Definition at line 1223 of file config_schemas.py.

regulator_corner_hz

float engine.pipeline.config_schemas.StabilityConfig.regulator_corner_hz = Field(default=3.0, gt=0, description="Regulator response corner frequency [Hz].")

static

Definition at line 1293 of file config_schemas.py.

regulator_enabled

bool engine.pipeline.config_schemas.StabilityConfig.regulator_enabled = Field(default=True, description="Model the dome regulator upstream of each tank in the chug loop.")

static

Definition at line 1292 of file config_schemas.py.

regulator_max_excursion_psi

float engine.pipeline.config_schemas.StabilityConfig.regulator_max_excursion_psi

static

Initial value:

=  Field(
        default=0.0, ge=0,
        description="Regulator outlet pressure excursion bound [psi]. Reporting only; not a pole-shifter.",
    )

Definition at line 1315 of file config_schemas.py.

regulator_Z_hf

float engine.pipeline.config_schemas.StabilityConfig.regulator_Z_hf

static

Initial value:

=  Field(
        default=0.0, ge=0,
        description=(
            "Regulator high-frequency series impedance [Pa*s/kg]. 0 = regulator NOT MODELLED: the feed "
            "sees an ideal pressure source, and the report says so instead of printing a with/without "
            "pair. Set it only from a measured step response (T6)."
        ),
    )

Definition at line 1307 of file config_schemas.py.

time_lag_model

Literal engine.pipeline.config_schemas.StabilityConfig.time_lag_model

static

Initial value:

=  Field(
        default="leonardi_dtl",
        description=(
            "Named model for the injection->heat-release conversion lag that drives the chug loop. "
            "'leonardi_dtl' is the double-time-lag decomposition tau_atom + tau_vap + tau_mix of "
            "Leonardi et al., Acta Astronautica 139 (2017); 'd2_law' is STAR's historical quiescent "
            "droplet lifetime, kept for reproducing older results. See "
            "scripts/chug_timelag_benchmark.py for the measurement that chose the default."
        ),
    )

Definition at line 1265 of file config_schemas.py.

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The documentation for this class was generated from the following file:

• EngineDesign/engine/pipeline/config_schemas.py