254 lines
8.6 KiB
Python
254 lines
8.6 KiB
Python
from __future__ import annotations
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import unittest
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from PythonModels.components.amesim_pneumatic import (
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HELIUM_PNEUMATIC_GAS,
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AmesimPneumaticGas,
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AmesimPneumaticOrifice,
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AmesimPneumaticVolume,
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AmesimVariablePneumaticVolume,
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cm3_to_m3,
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compressible_orifice_mass_flow,
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diameter_mm_to_area_m2,
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kg_to_g,
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liters_to_m3,
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m3_to_cm3,
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mm2_to_m2,
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)
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class AmesimPneumaticComponentsTest(unittest.TestCase):
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def test_unit_conversions(self) -> None:
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self.assertAlmostEqual(liters_to_m3(15.0), 0.015)
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self.assertAlmostEqual(m3_to_cm3(0.015), 15000.0)
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self.assertAlmostEqual(cm3_to_m3(15000.0), 0.015)
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self.assertAlmostEqual(kg_to_g(1.25), 1250.0)
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self.assertAlmostEqual(mm2_to_m2(78.5), 78.5e-6)
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self.assertAlmostEqual(diameter_mm_to_area_m2(10.0), 7.853981633974483e-5)
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def test_reference_enthalpy_uses_amesim_operating_temperature_baseline(self) -> None:
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gas = AmesimPneumaticGas(cp=5193.0, cv=3116.0)
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self.assertAlmostEqual(gas.specific_reference_enthalpy(298.15), 0.0)
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self.assertAlmostEqual(
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gas.specific_reference_enthalpy(290.2036),
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5193.0 * (290.2036 - 298.15),
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)
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self.assertAlmostEqual(
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gas.reference_temperature_from_specific_enthalpy(
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gas.specific_reference_enthalpy(287.7322),
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),
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287.7322,
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)
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def test_pressure_reference_enthalpy_includes_real_gas_departure(self) -> None:
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gas = AmesimPneumaticGas(cp=5193.0, cv=3116.0)
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ideal_reference_h = gas.specific_reference_enthalpy(287.7322)
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pressure_reference_h = gas.pressure_reference_enthalpy(13_839_965.0, 287.7322)
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self.assertAlmostEqual(ideal_reference_h, -54099.6354, delta=0.001)
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self.assertAlmostEqual(
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pressure_reference_h - ideal_reference_h,
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11936.1,
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delta=0.1,
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)
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def test_pressure_transport_enthalpy_restores_absolute_energy_offset(self) -> None:
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gas = HELIUM_PNEUMATIC_GAS
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pressure = 13_839_965.0
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temperature = 287.7322
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self.assertAlmostEqual(
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gas.pressure_transport_enthalpy(pressure, temperature),
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gas.pressure_reference_enthalpy(pressure, temperature)
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+ gas.cp * 298.15,
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)
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def test_reference_temperature_from_enthalpy_rejects_non_positive_cp(self) -> None:
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gas = AmesimPneumaticGas(cp=0.0, cv=3116.0)
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with self.assertRaisesRegex(ValueError, "cp must be positive"):
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gas.reference_temperature_from_specific_enthalpy(42.0)
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def test_volume_initial_state_matches_requested_pressure_temperature(self) -> None:
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volume = AmesimPneumaticVolume.from_liters(
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name="pn_general_chamber",
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volume_liters=57.0,
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p0=15.3e6,
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T0=293.15,
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)
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props = volume.properties()
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self.assertAlmostEqual(props.p, 15.3e6, delta=15.3e6 * 1.0e-12)
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self.assertAlmostEqual(props.T, 293.15)
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self.assertGreater(props.rho, 20.0)
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self.assertLess(props.rho, 30.0)
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def test_volume_reports_amesim_style_observables(self) -> None:
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volume = AmesimPneumaticVolume.from_liters(
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name="pn_general_chamber",
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volume_liters=57.0,
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p0=15.3e6,
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T0=293.15,
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)
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self.assertAlmostEqual(volume.volume_cm3(), 57000.0)
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self.assertAlmostEqual(
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volume.pressure_gauge_pa(reference_pressure_pa=101_300.0),
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15198700.0,
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)
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self.assertGreater(volume.gas_mass_g(), 1300.0)
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def test_volume_balances_two_connections_with_stream_enthalpy(self) -> None:
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volume = AmesimPneumaticVolume.from_liters(
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name="pn_general_chamber",
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volume_liters=57.0,
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p0=15.3e6,
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T0=293.15,
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)
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internal_h = volume.properties().h
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derivative = volume.derivatives_from_two_connections(
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port_a_m_flow=0.2,
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connected_h_a=internal_h + 1000.0,
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port_b_m_flow=-0.1,
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connected_h_b=internal_h - 1000.0,
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internal_h=internal_h,
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)
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self.assertAlmostEqual(derivative.m, 0.1)
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self.assertAlmostEqual(
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derivative.U,
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0.2 * (internal_h + 1000.0) - 0.1 * internal_h,
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)
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self.assertAlmostEqual(volume.port_a.p, volume.port_b.p)
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def test_volume_applies_amesim_heat_exchange_to_energy_derivative(self) -> None:
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volume = AmesimPneumaticVolume.from_liters(
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name="heated_chamber",
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volume_liters=15.0,
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p0=100000.0,
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T0=300.0,
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heat_transfer_coefficient=1500.0,
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heat_transfer_area=0.7,
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external_temperature_k=293.15,
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)
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props = volume.properties()
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derivative = volume.derivatives_from_two_connections(
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port_a_m_flow=0.0,
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connected_h_a=props.h,
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port_b_m_flow=0.0,
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connected_h_b=props.h,
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internal_h=props.h,
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)
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self.assertAlmostEqual(
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derivative.U,
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1500.0 * 0.7 * (293.15 - 300.0),
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)
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def test_variable_volume_tracks_external_volume(self) -> None:
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volume = AmesimVariablePneumaticVolume.from_liters(
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name="pn_c1_8",
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dead_volume_liters=15.0,
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p0=100000.0,
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T0=293.15,
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)
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self.assertAlmostEqual(volume.volume_cm3(), 15000.0)
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volume.set_external_volume_m3(cm3_to_m3(34242.54636512914))
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self.assertAlmostEqual(volume.volume_cm3(), 49242.54636512914)
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def test_variable_volume_boundary_work_uses_external_volume_rate(self) -> None:
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volume = AmesimVariablePneumaticVolume.from_liters(
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name="pn_c1_8",
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dead_volume_liters=15.0,
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p0=100000.0,
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T0=293.15,
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)
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props = volume.properties()
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volume.set_external_volume_m3(0.0, external_volume_rate_m3_s=2.0e-6)
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derivative = volume.derivatives_from_two_connections(
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port_a_m_flow=0.0,
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connected_h_a=props.h,
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port_b_m_flow=0.0,
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connected_h_b=props.h,
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internal_h=props.h,
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)
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self.assertAlmostEqual(derivative.m, 0.0)
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self.assertAlmostEqual(derivative.U, -props.p * 2.0e-6)
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def test_orifice_effective_area_clamps_opening(self) -> None:
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orifice = AmesimPneumaticOrifice.from_mm2(
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name="pn_variable_orifice",
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area_mm2=78.5,
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opening=1.4,
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)
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self.assertAlmostEqual(orifice.effective_area, 78.5e-6)
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orifice.opening = -0.25
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self.assertAlmostEqual(orifice.effective_area, 0.0)
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def test_orifice_returns_signed_mass_flow(self) -> None:
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orifice = AmesimPneumaticOrifice.from_mm2(
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name="pn_orifice_18",
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area_mm2=78.5,
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flow_coefficient=0.9,
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)
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forward = orifice.mass_flow(15.3e6, 1.0e6, 293.15)
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reverse = orifice.mass_flow(1.0e6, 15.3e6, 293.15)
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self.assertGreater(forward, 0.0)
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self.assertAlmostEqual(reverse, -forward)
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self.assertEqual(orifice.mass_flow(1.0e6, 1.0e6, 293.15), 0.0)
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def test_choked_flow_is_independent_of_lower_downstream_pressure(self) -> None:
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base = compressible_orifice_mass_flow(
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upstream_pressure=15.3e6,
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downstream_pressure=1.0e6,
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upstream_temperature=293.15,
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area=78.5e-6,
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flow_coefficient=0.9,
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gas=HELIUM_PNEUMATIC_GAS,
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)
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lower_back_pressure = compressible_orifice_mass_flow(
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upstream_pressure=15.3e6,
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downstream_pressure=0.1e6,
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upstream_temperature=293.15,
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area=78.5e-6,
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flow_coefficient=0.9,
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gas=HELIUM_PNEUMATIC_GAS,
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)
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self.assertGreater(base, 0.0)
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self.assertAlmostEqual(lower_back_pressure, base)
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def test_subcritical_flow_decreases_as_back_pressure_rises(self) -> None:
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low_back_pressure = compressible_orifice_mass_flow(
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upstream_pressure=1.0e6,
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downstream_pressure=0.6e6,
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upstream_temperature=293.15,
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area=78.5e-6,
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flow_coefficient=0.9,
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)
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high_back_pressure = compressible_orifice_mass_flow(
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upstream_pressure=1.0e6,
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downstream_pressure=0.9e6,
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upstream_temperature=293.15,
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area=78.5e-6,
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flow_coefficient=0.9,
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)
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self.assertGreater(low_back_pressure, high_back_pressure)
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self.assertGreater(high_back_pressure, 0.0)
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if __name__ == "__main__":
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unittest.main()
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