fix: seed PNVO pipe series pressure

tests/test_pressure_flow_solver_initialization.py

@@ -58,6 +58,58 @@ class PressureFlowSolverInitializationTests(unittest.TestCase):
             "specialSeriesPressureSeed",
         )
 
+    def test_pnvo_pnl0001_series_pressure_is_seeded_by_flow_balance(self) -> None:
+        medium = IdealGasMedium()
+        chamber = AmesimPnch023("source", medium, p0=15.3e6)
+        source_plug = AmesimPnpl01("source_closed")
+        valve = AmesimPnvo001SignalOpening(
+            "valve",
+            medium,
+            opening0=1.0,
+        )
+        valve.res.signal = 1.0
+        pipe = AmesimPnl0001("pipe", medium, p0=14.0e6)
+        storage_plug = AmesimPnpl01("storage_closed")
+        network = SimulationNetwork("pnvo-pnl0001-series")
+        for component in (chamber, source_plug, valve, pipe, storage_plug):
+            network.add_component(component)
+        network.connect("source_closed", "port_1", "source", "port_1")
+        network.connect("source", "port_2", "valve", "port_3")
+        network.connect("valve", "port_2", "pipe", "port_1")
+        network.connect("pipe", "port_2", "storage_closed", "port_1")
+        chamber.refresh_thermodynamic_ports()
+        pipe.refresh_thermodynamic_ports()
+
+        solver = PressureFlowSolver(network)
+        result = solver.solve()
+
+        self.assertTrue(result.success)
+        self.assertEqual(result.evaluations, 0)
+        self.assertGreater(valve.port_2.p, pipe.port_2.p)
+        self.assertLess(valve.port_2.p, chamber.port_2.p)
+        self.assertAlmostEqual(valve.port_2.p, pipe.port_1.p)
+        self.assertAlmostEqual(-valve.port_2.m_flow, pipe.port_1.m_flow)
+
+        previous_intermediate_pressure = valve.port_2.p
+        replay_pressure = 12.0e6
+        replay_temperature = 293.15
+        replay_mass = (
+            medium.density(replay_pressure, replay_temperature) * pipe.volume
+        )
+        pipe.state = VolumeState(
+            m=replay_mass,
+            U=replay_mass * medium.specific_internal_energy(replay_temperature),
+        )
+        pipe.refresh_thermodynamic_ports()
+
+        replay = solver.solve()
+
+        self.assertTrue(replay.success)
+        self.assertEqual(replay.evaluations, 0)
+        self.assertNotAlmostEqual(valve.port_2.p, previous_intermediate_pressure)
+        self.assertAlmostEqual(valve.port_2.p, pipe.port_1.p)
+        self.assertAlmostEqual(-valve.port_2.m_flow, pipe.port_1.m_flow)
+
     def test_dead_ended_pnl00r_is_seeded_at_zero_flow_pressure(self) -> None:
         medium = IdealGasMedium()
         pipe = AmesimPnl00r("resistance", medium)