Files
SystemSimulationApp/app/simulation/core/medium.py
T

367 lines
12 KiB
Python

from __future__ import annotations
from dataclasses import dataclass
from math import isfinite
from typing import Protocol, Sequence
from app.simulation.core.errors import RecoverableTrialStateError
from app.simulation.performance import profile_property
@dataclass(frozen=True)
class ThermodynamicProperties:
p: float
T: float
rho: float
u: float
h: float
@dataclass(frozen=True)
class ThermodynamicPropertyTangents:
"""Directional derivatives of a recovered thermodynamic state."""
p: tuple[float, ...]
T: tuple[float, ...]
rho: tuple[float, ...]
u: tuple[float, ...]
h: tuple[float, ...]
@property
def width(self) -> int:
return len(self.p)
@classmethod
def zeros(cls, width: int) -> "ThermodynamicPropertyTangents":
values = (0.0,) * width
return cls(p=values, T=values, rho=values, u=values, h=values)
@dataclass(frozen=True)
class ThermodynamicPropertiesLinearization:
"""Primal properties and a validity-checked directional linearization."""
properties: ThermodynamicProperties
tangents: ThermodynamicPropertyTangents
valid: bool = True
reason: str | None = None
class GasMedium(Protocol):
"""Thermodynamic contract required by pneumatic components.
``IdealGasMedium`` is the default implementation. Keeping the component
boundary structural allows a later helium/Peng-Robinson implementation to
be registered without changing every AMESim component constructor.
"""
name: str
R_gas: float
cp_ref: float
T_ref: float
@property
def cv(self) -> float: ...
@property
def gamma(self) -> float: ...
def cp_at_temperature(self, T: float) -> float: ...
def cv_at_temperature(self, T: float) -> float: ...
def density(self, p: float, T: float) -> float: ...
def isentropic_density_pressure_factor(
self,
p: float,
T: float,
downstream_pressure: float | None = None,
) -> float: ...
def dynamic_viscosity(self, T: float) -> float: ...
def specific_internal_energy(self, T: float) -> float: ...
def specific_internal_energy_at_pressure(self, p: float, T: float) -> float: ...
def specific_enthalpy(self, T: float) -> float: ...
def specific_enthalpy_at_pressure(self, p: float, T: float) -> float: ...
def temperature_from_internal_energy(self, u: float) -> float: ...
def temperature_from_enthalpy(self, h: float) -> float: ...
def temperature_from_pressure_enthalpy(self, p: float, h: float) -> float: ...
def temperature_from_mass_internal_energy(self, m: float, U: float) -> float: ...
def pressure(self, m: float, T: float, V: float) -> float: ...
def properties_from_mU(
self,
m: float,
U: float,
V: float,
) -> ThermodynamicProperties: ...
def linearize_properties_from_mU(
self,
m: float,
U: float,
V: float,
dm: Sequence[float],
dU: Sequence[float],
dV: Sequence[float],
*,
properties: ThermodynamicProperties | None = None,
) -> ThermodynamicPropertiesLinearization: ...
@dataclass(frozen=True)
class IdealGasMedium:
"""Temperature-dependent ideal-gas air approximation.
This is still not a strict clone of `Modelica.Media.Air.SimpleAir`.
The small linear `cp(T)` term is kept configurable for calibration, but the
current default is calibrated against the committed Testmodel baseline and
therefore falls back to the constant-heat-capacity limit.
"""
name: str = "SimpleAirApprox"
R_gas: float = 287.0
cp_ref: float = 1005.0
T_ref: float = 300.0
cp_slope: float = 0.0
viscosity_ref: float = 1.82e-5
viscosity_T_ref: float = 293.15
sutherland_constant: float = 110.4
@property
def cv(self) -> float:
return self.cv_at_temperature(self.T_ref)
@property
def gamma(self) -> float:
return self.cp_at_temperature(self.T_ref) / self.cv
def cp_at_temperature(self, T: float) -> float:
return self.cp_ref + self.cp_slope * (T - self.T_ref)
def cv_at_temperature(self, T: float) -> float:
return self.cp_at_temperature(T) - self.R_gas
@profile_property("density")
def density(self, p: float, T: float) -> float:
return p / (self.R_gas * T)
@profile_property("isentropic_density_pressure_factor")
def isentropic_density_pressure_factor(
self,
p: float,
T: float,
downstream_pressure: float | None = None,
) -> float:
del p
del downstream_pressure
cp = self.cp_at_temperature(T)
cv = self.cv_at_temperature(T)
return cv / cp
@profile_property("dynamic_viscosity")
def dynamic_viscosity(self, T: float) -> float:
"""Return dynamic viscosity using the default air Sutherland law."""
if T <= 0.0:
raise ValueError("Temperature must be positive.")
return (
self.viscosity_ref
* (T / self.viscosity_T_ref) ** 1.5
* (self.viscosity_T_ref + self.sutherland_constant)
/ (T + self.sutherland_constant)
)
@profile_property("specific_internal_energy")
def specific_internal_energy(self, T: float) -> float:
delta_T = T - self.T_ref
return (
self.cv * self.T_ref
+ self.cv * delta_T
+ 0.5 * self.cp_slope * delta_T * delta_T
)
@profile_property("specific_internal_energy_at_pressure")
def specific_internal_energy_at_pressure(self, p: float, T: float) -> float:
del p
return self.specific_internal_energy(T)
@profile_property("specific_enthalpy")
def specific_enthalpy(self, T: float) -> float:
delta_T = T - self.T_ref
return (
self.cp_ref * self.T_ref
+ self.cp_ref * delta_T
+ 0.5 * self.cp_slope * delta_T * delta_T
)
@profile_property("specific_enthalpy_at_pressure")
def specific_enthalpy_at_pressure(self, p: float, T: float) -> float:
del p
return self.specific_enthalpy(T)
def temperature_from_internal_energy(self, u: float) -> float:
reference_internal_energy = self.cv * self.T_ref
delta_u = u - reference_internal_energy
if abs(self.cp_slope) <= 1e-15:
return self.T_ref + delta_u / self.cv
a = 0.5 * self.cp_slope
b = self.cv
c = -delta_u
discriminant = max(b * b - 4.0 * a * c, 0.0)
positive_root = (-b + discriminant**0.5) / (2.0 * a)
negative_root = (-b - discriminant**0.5) / (2.0 * a)
delta_T = positive_root if abs(positive_root) <= abs(negative_root) else negative_root
return self.T_ref + delta_T
def temperature_from_enthalpy(self, h: float) -> float:
reference_enthalpy = self.cp_ref * self.T_ref
delta_h = h - reference_enthalpy
if abs(self.cp_slope) <= 1e-15:
return self.T_ref + delta_h / self.cp_ref
a = 0.5 * self.cp_slope
b = self.cp_ref
c = -delta_h
discriminant = max(b * b - 4.0 * a * c, 0.0)
positive_root = (-b + discriminant**0.5) / (2.0 * a)
negative_root = (-b - discriminant**0.5) / (2.0 * a)
delta_T = positive_root if abs(positive_root) <= abs(negative_root) else negative_root
return self.T_ref + delta_T
@profile_property("temperature_from_pressure_enthalpy")
def temperature_from_pressure_enthalpy(self, p: float, h: float) -> float:
del p
return self.temperature_from_enthalpy(h)
def temperature_from_mass_internal_energy(self, m: float, U: float) -> float:
if m <= 0.0:
raise RecoverableTrialStateError(
"Mass must stay positive when recovering temperature."
)
return self.temperature_from_internal_energy(U / m)
def pressure(self, m: float, T: float, V: float) -> float:
if V <= 0.0:
raise ValueError("Volume must stay positive.")
return m * self.R_gas * T / V
@profile_property("properties_from_mU")
def properties_from_mU(self, m: float, U: float, V: float) -> ThermodynamicProperties:
T = self.temperature_from_mass_internal_energy(m, U)
p = self.pressure(m, T, V)
rho = m / V
u = U / m
h = self.specific_enthalpy(T)
return ThermodynamicProperties(p=p, T=T, rho=rho, u=u, h=h)
def linearize_properties_from_mU(
self,
m: float,
U: float,
V: float,
dm: Sequence[float],
dU: Sequence[float],
dV: Sequence[float],
*,
properties: ThermodynamicProperties | None = None,
) -> ThermodynamicPropertiesLinearization:
"""Linearize properties_from_mU for several seed directions."""
dm_values = tuple(float(value) for value in dm)
dU_values = tuple(float(value) for value in dU)
dV_values = tuple(float(value) for value in dV)
if not (len(dm_values) == len(dU_values) == len(dV_values)):
raise ValueError("Thermodynamic tangent vectors must have equal lengths.")
props = properties or self.properties_from_mU(m, U, V)
width = len(dm_values)
expected_density = m / V
expected_internal_energy = U / m
if (
abs(props.rho - expected_density)
> 1.0e-12 * max(abs(expected_density), 1.0)
or abs(props.u - expected_internal_energy)
> 1.0e-12 * max(abs(expected_internal_energy), 1.0)
):
return ThermodynamicPropertiesLinearization(
properties=props,
tangents=ThermodynamicPropertyTangents.zeros(width),
valid=False,
reason="properties_primal_mismatch",
)
if not all(
isfinite(value)
for values in (dm_values, dU_values, dV_values)
for value in values
):
return ThermodynamicPropertiesLinearization(
properties=props,
tangents=ThermodynamicPropertyTangents.zeros(width),
valid=False,
reason="non_finite_tangent_input",
)
cv = self.cv_at_temperature(props.T)
cp = self.cp_at_temperature(props.T)
if not isfinite(cv) or not isfinite(cp) or cv <= 0.0 or cp <= 0.0:
return ThermodynamicPropertiesLinearization(
properties=props,
tangents=ThermodynamicPropertyTangents.zeros(width),
valid=False,
reason="non_positive_heat_capacity",
)
drho: list[float] = []
du: list[float] = []
dT: list[float] = []
dp: list[float] = []
dh: list[float] = []
for mass_tangent, energy_tangent, volume_tangent in zip(
dm_values,
dU_values,
dV_values,
strict=True,
):
density_tangent = mass_tangent / V - m * volume_tangent / (V * V)
internal_energy_tangent = (
energy_tangent / m - U * mass_tangent / (m * m)
)
temperature_tangent = internal_energy_tangent / cv
pressure_tangent = self.R_gas * (
props.T * density_tangent + props.rho * temperature_tangent
)
enthalpy_tangent = cp * temperature_tangent
drho.append(density_tangent)
du.append(internal_energy_tangent)
dT.append(temperature_tangent)
dp.append(pressure_tangent)
dh.append(enthalpy_tangent)
tangent_values = (*drho, *du, *dT, *dp, *dh)
valid = all(isfinite(value) for value in tangent_values)
return ThermodynamicPropertiesLinearization(
properties=props,
tangents=ThermodynamicPropertyTangents(
p=tuple(dp),
T=tuple(dT),
rho=tuple(drho),
u=tuple(du),
h=tuple(dh),
),
valid=valid,
reason=None if valid else "non_finite_property_tangent",
)