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SystemSimulationApp/app/simulation/components/amesim/mechanical/pistons.py
T

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7.9 KiB
Python

from __future__ import annotations
from collections.abc import Mapping
from math import pi
from app.simulation.components.amesim.gases import (
AMESIM_GAS_INDEX_PARAMETER,
normalize_amesim_gas_index,
)
from app.simulation.core.base import AlgebraicComponent
from app.simulation.core.catalog import ComponentDisplaySpec, PortDisplaySpec
from app.simulation.core.equations import EquationResidual
from app.simulation.core.metadata import ParameterDefinition, ResultVariableDefinition
from app.simulation.core.medium import GasMedium
from app.simulation.core.ports import PortDefinition
AMESIM_REFERENCE_PRESSURE_PA = 101300.0
class AmesimPnrp17(AlgebraicComponent):
"""AMESim PNRP17 pneumatic piston with two mechanical faces.
Mechanical ports 2/5 share the piston-side motion and ports 3/4 share the
cylinder-side motion. The pneumatic port contributes its swept volume and
volume rate to the connected variable-volume chamber.
"""
MODEL_TYPE = "amesim_pnrp17"
MODEL_VERSION = "0.1.0"
PORTS = (
PortDefinition.pneumatic("port_1", nominal_role="bidirectional"),
PortDefinition.mechanical_translational("port_2"),
PortDefinition.mechanical_translational("port_3"),
PortDefinition.mechanical_translational("port_4"),
PortDefinition.mechanical_translational("port_5"),
)
PARAMETERS = (
AMESIM_GAS_INDEX_PARAMETER,
ParameterDefinition(
"dp",
0.2,
label="活塞直径",
quantity="length",
unit="m",
minimum=0.0,
minimum_exclusive=True,
description="活塞外径;与活塞杆直径共同确定有效受压面积。",
),
ParameterDefinition(
"dr",
0.001,
label="活塞杆直径",
quantity="length",
unit="m",
minimum=0.0,
description="穿过气室一侧的活塞杆直径,必须不大于活塞直径。",
),
ParameterDefinition(
"x0",
0.0,
label="初始腔长",
quantity="length",
unit="m",
description="机械端位移均为零时的气动腔长度。",
),
)
RESULT_VARIABLES = (
ResultVariableDefinition("volume", "扫掠容积", "volume", "m3", "derived", 10),
ResultVariableDefinition(
"volume_flow",
"扫掠容积变化率",
"volume_flow",
"m3/s",
"derived",
20,
),
ResultVariableDefinition("length", "气动腔长度", "length", "m", "derived", 30),
ResultVariableDefinition(
"pressure_force",
"气压力",
"force",
"N",
"derived",
40,
),
)
DISPLAY = ComponentDisplaySpec(
label="PNRP17 气动活塞",
library_id="amesim",
category_id="mechanical",
symbol="amesim_pnrp17",
ports=(
PortDisplaySpec("port_1", "left", order=10),
PortDisplaySpec("port_3", "left", order=20),
PortDisplaySpec("port_4", "left", order=30),
PortDisplaySpec("port_2", "right", order=40),
PortDisplaySpec("port_5", "right", order=50),
),
order=60,
)
def __init__(
self,
name: str,
medium: GasMedium,
*,
gi: float = 0.0,
dp: float = 0.2,
dr: float = 0.001,
x0: float = 0.0,
) -> None:
super().__init__(name=name)
self.set_parameter_values({"gi": gi, "dp": dp, "dr": dr, "x0": x0})
self.medium = medium
self.gi = normalize_amesim_gas_index(gi)
self.dp = float(dp)
self.dr = float(dr)
self.x0 = float(x0)
if self.dr > self.dp:
raise ValueError("PNRP17 rod diameter dr must not exceed piston diameter dp.")
for definition in self.PORTS:
port = self.register_declared_port(definition.name)
setattr(self, definition.name, port)
self.port_1.h_outflow = medium.specific_enthalpy(medium.T_ref)
@classmethod
def create(
cls,
*,
name: str,
medium: GasMedium,
parameters: Mapping[str, float],
) -> "AmesimPnrp17":
return cls(name=name, medium=medium, **dict(parameters))
@property
def effective_area(self) -> float:
return pi * (self.dp * self.dp - self.dr * self.dr) / 4.0
@property
def chamber_length(self) -> float:
return self.x0 + self.port_5.x - self.port_4.x
@property
def chamber_volume(self) -> float:
return self.effective_area * self.chamber_length
@property
def chamber_volume_flow(self) -> float:
return self.effective_area * (self.port_5.v - self.port_4.v)
@property
def pressure_force(self) -> float:
return (self.port_1.p - AMESIM_REFERENCE_PRESSURE_PA) * self.effective_area
def pressure_flow_equation_residuals(self) -> tuple[EquationResidual, ...]:
effort_pairs = (("port_2", "port_5"), ("port_3", "port_4"))
residuals: list[EquationResidual] = [
EquationResidual(
id=f"{self.name}:pneumatic_zero_mass_flow",
owner="component",
owner_id=self.name,
relation="constitutive",
variables=(f"{self.name}.port_1.m_flow",),
role="flow",
value=self.port_1.m_flow,
)
]
for first_name, second_name in effort_pairs:
first = self.get_port(first_name)
second = self.get_port(second_name)
for variable in ("x", "v"):
residuals.append(
EquationResidual(
id=f"{self.name}:{first_name}_{second_name}_{variable}_equal",
owner="component",
owner_id=self.name,
relation="equal",
variables=(
f"{self.name}.{first_name}.{variable}",
f"{self.name}.{second_name}.{variable}",
),
role="effort",
value=getattr(first, variable) - getattr(second, variable),
)
)
force = self.pressure_force
residuals.extend(
(
EquationResidual(
id=f"{self.name}:piston_side_force_balance",
owner="component",
owner_id=self.name,
relation="constitutive",
variables=(f"{self.name}.port_2.f", f"{self.name}.port_5.f", f"{self.name}.port_1.p"),
role="flow",
value=self.port_2.f + self.port_5.f + force,
),
EquationResidual(
id=f"{self.name}:cylinder_side_force_balance",
owner="component",
owner_id=self.name,
relation="constitutive",
variables=(f"{self.name}.port_3.f", f"{self.name}.port_4.f", f"{self.name}.port_1.p"),
role="flow",
value=self.port_3.f + self.port_4.f - force,
),
)
)
return tuple(residuals)
def pneumatic_volume_outputs(self) -> Mapping[str, tuple[float, float]]:
return {"port_1": (self.chamber_volume, self.chamber_volume_flow)}
def update_stream_outflows(self, connected_h: Mapping[str, float]) -> None:
self.port_1.h_outflow = connected_h.get(
"port_1",
self.medium.specific_enthalpy(self.medium.T_ref),
)
def component_result_values(self) -> Mapping[str, float]:
return {
"volume": self.chamber_volume,
"volume_flow": self.chamber_volume_flow,
"length": self.chamber_length,
"pressure_force": self.pressure_force,
}