添加联合仿真内容，修改index.md
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"""Example system simulations."""
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"""
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Coupled cryogenic tank and upstream high-pressure helium cylinder example.
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The cryogenic tank still enforces a constant ullage pressure P_work. The
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helium inlet temperature is fixed to cryo_tank.config.T_IN_HE. The resulting
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tank-side helium boundary is passed upstream to the cylinder as the imposed
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mass and energy outflow condition.
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"""
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import os
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import sys
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from dataclasses import dataclass
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import matplotlib
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matplotlib.use("Agg")
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import matplotlib.pyplot as plt
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import numpy as np
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from scipy.integrate import solve_ivp
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_REPO_ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
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_SRC_DIR = os.path.join(_REPO_ROOT, "src")
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if _SRC_DIR not in sys.path:
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sys.path.insert(0, _SRC_DIR)
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from cryo_tank.config import ( # noqa: E402
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V_TOTAL, H_TANK, P_WORKING, T_INIT, ULLAGE_FRACTION,
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MDOT_IN_LN2, T_IN_LN2, MDOT_OUT_LN2,
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H_CONV_SURFACE, T_ENV, A_TOTAL, T_IN_HE,
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T_END, RTOL, ATOL,
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)
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from cryo_tank import properties as prop # noqa: E402
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from cryo_tank.heat_leak import MLIHeatLeak # noqa: E402
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from cryo_tank.tank_model import CryoTank # noqa: E402
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from cylinder import HighPressureGasCylinder # noqa: E402
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OUTPUT_DIR = os.path.join(_REPO_ROOT, "results", "examples")
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@dataclass(frozen=True)
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class HeliumBoundary:
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"""Helium inlet boundary passed between the tank and cylinder."""
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mdot_to_tank: float
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edot_to_tank: float
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source_pressure: float
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source_temperature: float
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source_enthalpy: float
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boundary_enthalpy: float
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tank_inlet_pressure: float
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tank_inlet_temperature: float
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def build_default_tank():
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"""Build the default cryogenic tank used by the example."""
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heat_leak = MLIHeatLeak(A_total=A_TOTAL, q_mli=1.0)
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return CryoTank(
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V_total=V_TOTAL,
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H_tank=H_TANK,
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P_work=P_WORKING,
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T_init=T_INIT,
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ullage_fraction=ULLAGE_FRACTION,
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mdot_in_ln2=MDOT_IN_LN2,
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T_in_ln2=T_IN_LN2,
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mdot_out_ln2=MDOT_OUT_LN2,
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T_in_he=T_IN_HE,
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h_conv=H_CONV_SURFACE,
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T_env=T_ENV,
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heat_leak_model=heat_leak,
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)
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def sync_fixed_he_inlet_boundary(tank):
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"""Apply the fixed tank helium inlet boundary from cryo_tank.config."""
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boundary_h = prop.he_h(T_IN_HE, tank.P_work)
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tank.T_in_he = T_IN_HE
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tank.h_in_he = boundary_h
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return boundary_h, T_IN_HE
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def _set_cylinder_conserved_state(cylinder, mass, U):
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cylinder.mass = mass
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cylinder.U = U
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cylinder._update_state()
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def _heat_terms(tank, info):
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T_liq = info['T_liq']
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T_ull = info['T_ull']
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liquid_level = info['liquid_level']
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Q_liq_to_ull = tank.h_conv * tank.A_cross * (T_liq - T_ull)
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Q_leak = tank.heat_leak_model.compute(T_liq, tank.T_env)
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A_wet, A_dry = tank.wetted_areas(liquid_level)
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A_total_current = A_wet + A_dry
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if A_total_current > 0.0:
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Q_leak_liq = Q_leak * A_wet / A_total_current
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Q_leak_ull = Q_leak * A_dry / A_total_current
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else:
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Q_leak_liq = 0.0
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Q_leak_ull = 0.0
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return Q_liq_to_ull, Q_leak, Q_leak_liq, Q_leak_ull
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def tank_rates_and_boundary(tank, cylinder, y_tank):
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"""Return tank ODE rates and the coupled helium inlet boundary."""
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boundary_h, tank_inlet_T = sync_fixed_he_inlet_boundary(tank)
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info = tank.derive(y_tank)
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Q_liq_to_ull, _, Q_leak_liq, Q_leak_ull = _heat_terms(tank, info)
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dm_liq_dt = tank.dm_liq_dt
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dU_liq_dt = tank._liquid_energy_rate(info, Q_liq_to_ull, Q_leak_liq)
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dT_ull_dt, mdot_he = tank._solve_ullage_temperature_rate(
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info, Q_liq_to_ull, Q_leak_ull, dU_liq_dt
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)
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boundary = HeliumBoundary(
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mdot_to_tank=mdot_he,
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edot_to_tank=mdot_he * boundary_h,
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source_pressure=cylinder.P,
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source_temperature=cylinder.T,
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source_enthalpy=cylinder.h,
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boundary_enthalpy=boundary_h,
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tank_inlet_pressure=tank.P_work,
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tank_inlet_temperature=tank_inlet_T,
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)
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return np.array([dm_liq_dt, dU_liq_dt, dT_ull_dt]), boundary
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def run_system(t_end=T_END, rtol=RTOL, atol=ATOL, max_step=10.0,
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tank=None, cylinder=None):
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"""Run the coupled tank-cylinder system.
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Returns a history dict. The cylinder state is included as conserved state
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variables ``m_cylinder`` and ``U_cylinder`` plus derived pressure,
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temperature, density, and boundary quantities.
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"""
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cylinder = HighPressureGasCylinder() if cylinder is None else cylinder
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tank = build_default_tank() if tank is None else tank
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sync_fixed_he_inlet_boundary(tank)
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y0 = np.array([
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*tank.initial_state(),
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cylinder.mass,
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cylinder.U,
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])
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def rhs(t, y):
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_set_cylinder_conserved_state(cylinder, y[3], y[4])
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tank_rates, boundary = tank_rates_and_boundary(tank, cylinder, y[:3])
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cylinder_mass_rate = -boundary.mdot_to_tank
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cylinder_energy_rate = -boundary.edot_to_tank
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return np.array([
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tank_rates[0],
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tank_rates[1],
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tank_rates[2],
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cylinder_mass_rate,
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cylinder_energy_rate,
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])
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def liquid_empty_event(t, y):
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return y[0]
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liquid_empty_event.terminal = True
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liquid_empty_event.direction = -1
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def cylinder_pressure_event(t, y):
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_set_cylinder_conserved_state(cylinder, y[3], y[4])
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return cylinder.P - tank.P_work
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cylinder_pressure_event.terminal = True
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cylinder_pressure_event.direction = -1
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sol = solve_ivp(
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rhs,
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[0.0, t_end],
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y0,
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method='RK45',
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rtol=rtol,
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atol=atol,
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max_step=max_step,
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events=[liquid_empty_event, cylinder_pressure_event],
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dense_output=True,
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)
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if not sol.success:
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raise RuntimeError(f"Coupled solve failed: {sol.message}")
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return post_process_history(tank, cylinder, sol.t, sol.y)
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def post_process_history(tank, cylinder, t, y):
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"""Compute tank, cylinder, and boundary histories from solver output."""
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n = len(t)
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history = {
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't': t,
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'm_liq': y[0],
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'U_liq': y[1],
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'T_ull': y[2],
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'm_cylinder': y[3],
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'U_cylinder': y[4],
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'T_liq': np.zeros(n),
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'T_tank_liq': np.zeros(n),
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'T_tank_ullage': np.zeros(n),
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'fill_fraction': np.zeros(n),
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'liquid_level': np.zeros(n),
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'V_ull': np.zeros(n),
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'm_He': np.zeros(n),
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'U_ull': np.zeros(n),
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'P_tank': np.zeros(n),
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'mdot_He': np.zeros(n),
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'mdot_tank_inlet': np.zeros(n),
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'mdot_cylinder_out': np.zeros(n),
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'edot_He': np.zeros(n),
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'P_cylinder': np.zeros(n),
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'T_cylinder': np.zeros(n),
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'rho_cylinder': np.zeros(n),
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'h_cylinder': np.zeros(n),
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'P_he_source': np.zeros(n),
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'T_he_source': np.zeros(n),
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'h_he_source': np.zeros(n),
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'P_he_boundary': np.zeros(n),
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'T_he_boundary': np.zeros(n),
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'h_he_boundary': np.zeros(n),
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'P_he_tank_inlet': np.zeros(n),
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'T_he_tank_inlet': np.zeros(n),
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'pressure_margin': np.zeros(n),
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'Q_liq_to_ull': np.zeros(n),
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'Q_leak': np.zeros(n),
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'Q_leak_liq': np.zeros(n),
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'Q_leak_ull': np.zeros(n),
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}
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for i in range(n):
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_set_cylinder_conserved_state(cylinder, y[3, i], y[4, i])
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tank_rates, boundary = tank_rates_and_boundary(tank, cylinder, y[:3, i])
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info = tank.derive(y[:3, i])
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Q_liq_to_ull, Q_leak, Q_leak_liq, Q_leak_ull = _heat_terms(tank, info)
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history['T_liq'][i] = info['T_liq']
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history['T_tank_liq'][i] = info['T_liq']
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history['T_tank_ullage'][i] = info['T_ull']
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history['fill_fraction'][i] = info['fill_fraction']
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history['liquid_level'][i] = info['liquid_level']
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history['V_ull'][i] = info['V_ull']
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history['m_He'][i] = info['m_He']
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history['U_ull'][i] = info['U_ull']
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history['P_tank'][i] = info['P_He']
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history['mdot_He'][i] = boundary.mdot_to_tank
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history['mdot_tank_inlet'][i] = boundary.mdot_to_tank
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history['mdot_cylinder_out'][i] = boundary.mdot_to_tank
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history['edot_He'][i] = boundary.edot_to_tank
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history['P_cylinder'][i] = cylinder.P
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history['T_cylinder'][i] = cylinder.T
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history['rho_cylinder'][i] = cylinder.rho
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history['h_cylinder'][i] = cylinder.h
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history['P_he_source'][i] = boundary.source_pressure
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history['T_he_source'][i] = boundary.source_temperature
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history['h_he_source'][i] = boundary.source_enthalpy
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history['P_he_boundary'][i] = boundary.tank_inlet_pressure
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history['T_he_boundary'][i] = boundary.tank_inlet_temperature
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history['h_he_boundary'][i] = boundary.boundary_enthalpy
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history['P_he_tank_inlet'][i] = boundary.tank_inlet_pressure
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history['T_he_tank_inlet'][i] = boundary.tank_inlet_temperature
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history['pressure_margin'][i] = boundary.source_pressure - boundary.tank_inlet_pressure
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history['Q_liq_to_ull'][i] = Q_liq_to_ull
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history['Q_leak'][i] = Q_leak
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history['Q_leak_liq'][i] = Q_leak_liq
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history['Q_leak_ull'][i] = Q_leak_ull
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return history
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def _save_figure(fig, path):
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os.makedirs(os.path.dirname(path), exist_ok=True)
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fig.tight_layout()
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fig.savefig(path, dpi=140)
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plt.close(fig)
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def plot_requested_outputs(history, output_dir):
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"""Plot tank and cylinder pressure, temperature, and mass-flow histories."""
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os.makedirs(output_dir, exist_ok=True)
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t = history['t']
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fig, (ax_p, ax_t) = plt.subplots(2, 1, figsize=(10, 7), sharex=True)
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ax_p.plot(t, history['P_tank'] / 1e6)
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ax_p.set_ylabel('Tank pressure [MPa]')
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ax_p.grid(True)
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ax_t.plot(t, history['T_tank_liq'], label='Liquid')
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ax_t.plot(t, history['T_tank_ullage'], label='Ullage')
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ax_t.plot(t, history['T_he_tank_inlet'], label='He inlet', linestyle='--')
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ax_t.set_xlabel('Time [s]')
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ax_t.set_ylabel('Tank temperature [K]')
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ax_t.grid(True)
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ax_t.legend()
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_save_figure(
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fig, os.path.join(output_dir, 'tank_pressure_temperature.png')
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)
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fig, ax = plt.subplots(figsize=(10, 4.5))
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ax.plot(t, history['mdot_tank_inlet'] * 1000.0)
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ax.set_xlabel('Time [s]')
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ax.set_ylabel('Tank inlet He mass flow [g/s]')
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ax.grid(True)
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_save_figure(fig, os.path.join(output_dir, 'tank_inlet_mass_flow.png'))
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fig, (ax_p, ax_t) = plt.subplots(2, 1, figsize=(10, 7), sharex=True)
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ax_p.plot(t, history['P_cylinder'] / 1e6)
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ax_p.set_ylabel('Cylinder pressure [MPa]')
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ax_p.grid(True)
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ax_t.plot(t, history['T_cylinder'])
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ax_t.set_xlabel('Time [s]')
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ax_t.set_ylabel('Cylinder temperature [K]')
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ax_t.grid(True)
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_save_figure(
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fig, os.path.join(output_dir, 'cylinder_pressure_temperature.png')
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)
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fig, ax = plt.subplots(figsize=(10, 4.5))
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ax.plot(t, history['mdot_cylinder_out'] * 1000.0)
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ax.set_xlabel('Time [s]')
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ax.set_ylabel('Cylinder outlet He mass flow [g/s]')
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ax.grid(True)
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_save_figure(fig, os.path.join(output_dir, 'cylinder_mass_flow.png'))
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def save_history_csv(history, path):
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"""Save a 1D history dictionary as CSV."""
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os.makedirs(os.path.dirname(path), exist_ok=True)
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names = list(history.keys())
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data = np.column_stack([np.asarray(history[name]) for name in names])
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np.savetxt(path, data, delimiter=',', header=','.join(names), comments='')
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def save_history_npz(history, path):
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"""Save a history dictionary as compressed NPZ."""
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os.makedirs(os.path.dirname(path), exist_ok=True)
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np.savez_compressed(path, **history)
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def main():
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cylinder = HighPressureGasCylinder()
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tank = build_default_tank()
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print("Coupled cryo tank + upstream He cylinder")
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print(f" t_end = {T_END:.3f} s")
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print(f" tank P_work = {tank.P_work / 1e6:.4f} MPa")
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print(f" cylinder: P = {cylinder.P / 1e6:.4f} MPa, T = {cylinder.T:.2f} K, "
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f"m = {cylinder.mass:.4f} kg")
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print()
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history = run_system(tank=tank, cylinder=cylinder)
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csv_path = os.path.join(OUTPUT_DIR, "cryo_tank_cylinder_system.csv")
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npz_path = os.path.join(OUTPUT_DIR, "cryo_tank_cylinder_system.npz")
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save_history_csv(history, csv_path)
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save_history_npz(history, npz_path)
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plot_requested_outputs(history, OUTPUT_DIR)
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print("Simulation complete:")
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print(f" t_final = {history['t'][-1]:.1f} s")
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print(f" tank fill_fraction: {history['fill_fraction'][0]:.1%} -> "
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f"{history['fill_fraction'][-1]:.1%}")
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print(f" tank P: {history['P_tank'][0] / 1e6:.4f} -> "
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f"{history['P_tank'][-1] / 1e6:.4f} MPa")
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print(f" tank T_liq: {history['T_tank_liq'][0]:.2f} -> "
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f"{history['T_tank_liq'][-1]:.2f} K")
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print(f" tank T_ull: {history['T_tank_ullage'][0]:.2f} -> "
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f"{history['T_tank_ullage'][-1]:.2f} K")
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print(f" tank inlet He mdot: {history['mdot_tank_inlet'][0] * 1000:.5f} -> "
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f"{history['mdot_tank_inlet'][-1] * 1000:.5f} g/s")
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print(f" cylinder P: {history['P_cylinder'][0] / 1e6:.4f} -> "
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f"{history['P_cylinder'][-1] / 1e6:.4f} MPa")
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print(f" cylinder T: {history['T_cylinder'][0]:.2f} -> "
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f"{history['T_cylinder'][-1]:.2f} K")
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print(f" cylinder outlet He mdot: {history['mdot_cylinder_out'][0] * 1000:.5f} -> "
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f"{history['mdot_cylinder_out'][-1] * 1000:.5f} g/s")
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print(f" cylinder mass: {history['m_cylinder'][0]:.4f} -> "
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f"{history['m_cylinder'][-1]:.4f} kg")
|
||||
print(f" tank-side He inlet T: {history['T_he_tank_inlet'][0]:.2f} -> "
|
||||
f"{history['T_he_tank_inlet'][-1]:.2f} K")
|
||||
print(f" fixed He boundary h: {history['h_he_boundary'][0]:.2f} -> "
|
||||
f"{history['h_he_boundary'][-1]:.2f} J/kg")
|
||||
print(f"\nOutputs written to {OUTPUT_DIR}/")
|
||||
|
||||
|
||||
if __name__ == "__main__":
|
||||
main()
|
||||
Reference in new issue
Block a user