def test_pipe_vaporphase():
m = pyo.ConcreteModel()
m.fs = FlowsheetBlock(default={"dynamic": False})
m.fs.properties = iapws95.Iapws95ParameterBlock()
m.fs.unit = WaterPipe(default={
"dynamic": False,
"property_package": m.fs.properties,
"has_holdup": True,
"has_heat_transfer": False,
"has_pressure_change": True,
"water_phase": 'Vap',
"contraction_expansion_at_end": 'None'
})
m.fs.unit.diameter.fix(0.04)
m.fs.unit.length.fix(40)
m.fs.unit.number_of_pipes.fix(100)
m.fs.unit.elevation_change.fix(25)
m.fs.unit.fcorrection_dp.fix(1.0)
state_args = {'flow_mol': 10000,
'pressure': 3.6e6,
'enth_mol': 53942}
initialization_tester(m, dof=3, state_args=state_args)
m.fs.unit.inlet.enth_mol.fix()
m.fs.unit.inlet.flow_mol.fix()
m.fs.unit.inlet.pressure.fix()
assert degrees_of_freedom(m) == 0
results = solver.solve(m, tee=True)
# Check for optimal solution
assert results.solver.termination_condition == \
pyo.TerminationCondition.optimal
assert results.solver.status == pyo.SolverStatus.ok
assert pyo.value(m.fs.unit.control_volume.properties_in[0].vapor_frac) == 1
# check material balance
assert (pytest.approx(pyo.value(m.fs.unit.control_volume.properties_in[0].
flow_mol - m.fs.unit.control_volume.
properties_out[0].flow_mol),
abs=1e-3) == 0)
# pressure drop
assert (pytest.approx(-539105.588, abs=1e-3) == pyo.value(m.fs.unit.
deltaP[0]))
# check energy balance
assert (pytest.approx(
pyo.value(m.fs.unit.control_volume.properties_in[0].enth_mol
- m.fs.unit.control_volume.properties_out[0].enth_mol),
abs=1e-3) == 0)
def build_unit():
m = pyo.ConcreteModel()
m.fs = FlowsheetBlock(default={"dynamic": False})
m.fs.properties = iapws95.Iapws95ParameterBlock()
m.fs.unit = WaterPipe(default={
"dynamic": False,
"property_package": m.fs.properties,
"has_holdup": True,
"has_heat_transfer": False,
"has_pressure_change": True,
"water_phase": 'Liq',
"contraction_expansion_at_end": 'contraction'
})
return m
def test_pipe_expansion():
m = pyo.ConcreteModel()
m.fs = FlowsheetBlock(default={"dynamic": False})
m.fs.properties = iapws95.Iapws95ParameterBlock()
m.fs.unit = WaterPipe(default={
"dynamic": False,
"property_package": m.fs.properties,
"has_holdup": True,
"has_heat_transfer": False,
"has_pressure_change": True,
"water_phase": 'Liq',
"contraction_expansion_at_end": 'expansion'
})
m.fs.unit.diameter.fix(0.04)
m.fs.unit.length.fix(40)
m.fs.unit.number_of_pipes.fix(100)
m.fs.unit.elevation_change.fix(25)
m.fs.unit.area_ratio.fix(0.5)
m.fs.unit.fcorrection_dp.fix(1.0)
state_args = {'flow_mol': 10000,
'pressure': 1.3e7,
'enth_mol': 18000}
initialization_tester(m, dof=3, state_args=state_args)
m.fs.unit.inlet.enth_mol.fix()
m.fs.unit.inlet.flow_mol.fix()
m.fs.unit.inlet.pressure.fix()
assert degrees_of_freedom(m) == 0
results = solver.solve(m, tee=True)
# Check for optimal solution
assert pyo.check_optimal_termination(results)
# check material balance
assert (pytest.approx(pyo.value(m.fs.unit.control_volume.properties_in[0].
flow_mol - m.fs.unit.control_volume.
properties_out[0].flow_mol),
abs=1e-3) == 0)
# pressure drop
assert (pytest.approx(-224306.548, abs=1e-3) == pyo.value(m.fs.unit.
deltaP[0]))
# check energy balance
assert (pytest.approx(
pyo.value(m.fs.unit.control_volume.properties_in[0].enth_mol
- m.fs.unit.control_volume.properties_out[0].enth_mol),
abs=1e-3) == 0)