def build_watertank_simple():
# Create a Concrete Model as the top level object
m = pyo.ConcreteModel()
# Add a flowsheet object to the model
m.fs = FlowsheetBlock(default={"dynamic": False})
# Add property packages to flowsheet library
m.fs.prop_water = iapws95.Iapws95ParameterBlock()
m.fs.unit = WaterTank(default={"property_package": m.fs.prop_water,
"has_holdup": False,
"has_heat_transfer": True,
"has_pressure_change": True})
# fix inputs for simple tank
m.fs.unit.tank_cross_sect_area.fix(1.14) # tank cross sectional area
m.fs.unit.tank_level[:].fix(0.6) # tank level
m.fs.unit.heat_duty[:].fix(0.0) # assume no heat loss
return m
def build_watertank_vert_cylin():
# Create a Concrete Model as the top level object
m = pyo.ConcreteModel()
# Add a flowsheet object to the model
m.fs = FlowsheetBlock(default={"dynamic": False})
# Add property packages to flowsheet library
m.fs.prop_water = iapws95.Iapws95ParameterBlock()
m.fs.unit = WaterTank(default={"tank_type": "vertical_cylindrical_tank",
"property_package": m.fs.prop_water,
"has_holdup": False,
"has_heat_transfer": True,
"has_pressure_change": True})
# fix inputs for horizontal cylindrical tank
m.fs.unit.tank_diameter.fix(1.2) # tank diameter
m.fs.unit.tank_level[:].fix(0.6) # tank level
m.fs.unit.heat_duty[:].fix(0.0) # assume no heat loss
return m
def get_model(dynamic=False):
m = pyo.ConcreteModel(name="Testing PID controller model")
if dynamic:
m.dynamic = True
m.fs = FlowsheetBlock(default={
"dynamic": True,
"time_set": [0, 50, 1000],
"time_units": pyo.units.s
})
else:
m.dynamic = False
m.fs = FlowsheetBlock(default={"dynamic": False})
m.fs.prop_water = iapws95.Iapws95ParameterBlock()
# water pump
m.fs.pump = WaterPump(default={
"dynamic": False,
"property_package": m.fs.prop_water,
})
# water tank
m.fs.tank = WaterTank(
default={
"tank_type": "simple_tank",
"has_holdup": True,
"property_package": m.fs.prop_water,
})
m.fs.valve = WaterValve(
default={
"dynamic": False,
"has_holdup": False,
"phase": "Liq",
"property_package": m.fs.prop_water
})
if dynamic:
m.fs.controller = PIDController(
default={
"pv": m.fs.tank.tank_level,
"mv": m.fs.valve.valve_opening,
"type": 'PI',
"bounded_output": False
})
m.discretizer = pyo.TransformationFactory('dae.finite_difference')
m.discretizer.apply_to(m, nfe=20, wrt=m.fs.time, scheme="BACKWARD")
m.fs.controller.gain_p.fix(-1e-1)
m.fs.controller.gain_i.fix(-1e-2)
m.fs.controller.setpoint.fix(5)
m.fs.controller.mv_ref.fix(0.5)
m.fs.controller.integral_of_error[0].fix(0)
m.fs.pump_to_tank = Arc(source=m.fs.pump.outlet,
destination=m.fs.tank.inlet)
m.fs.tank_to_valve = Arc(source=m.fs.tank.outlet,
destination=m.fs.valve.inlet)
pyo.TransformationFactory('network.expand_arcs').apply_to(m.fs)
m.fs.pump.efficiency_isentropic.fix(0.8)
m.fs.pump.deltaP.fix(5e4)
m.fs.tank.tank_cross_sect_area.fix(20)
m.fs.tank.tank_level[:].fix(5)
m.fs.valve.Cv.fix(63.4676)
m.fs.valve.valve_opening.fix(0.5)
m.fs.pump.inlet.flow_mol[:].fix(7000)
m.fs.pump.inlet.enth_mol[:].fix(3924)
m.fs.pump.inlet.pressure[:].fix(1e7)
m.fs.valve.outlet.pressure[:].fix(10050000)
set_scaling_factors(m)
if dynamic:
m.fs.tank.set_initial_condition()
if not dynamic:
m.fs.pump.initialize()
m.fs.tank.inlet.flow_mol[:].value = m.fs.pump.outlet.flow_mol[0].value
m.fs.tank.inlet.enth_mol[:].value = m.fs.pump.outlet.enth_mol[0].value
m.fs.tank.inlet.pressure[:].value = m.fs.pump.outlet.pressure[0].value
m.fs.tank.initialize()
m.fs.valve.inlet.flow_mol[:].value = m.fs.tank.outlet.flow_mol[0].value
m.fs.valve.inlet.enth_mol[:].value = m.fs.tank.outlet.enth_mol[0].value
m.fs.valve.inlet.pressure[:].value = m.fs.tank.outlet.pressure[0].value
# Solve for outlet pressure
m.fs.valve.initialize()
m.fs.valve.valve_opening.unfix()
dof = degrees_of_freedom(m)
assert dof == 0
solver = pyo.SolverFactory("ipopt")
solver.options = {
"tol": 1e-7,
"linear_solver": "ma27",
"max_iter": 100,
}
solver.solve(m, tee=True)
else:
m.fs.tank.tank_level.unfix()
m.fs.tank.tank_level[0].fix()
m.fs.valve.valve_opening.unfix()
return m