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

227 lines
7.2 KiB
Python

from __future__ import annotations
from dataclasses import dataclass
from typing import Protocol
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
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: ...
@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)