PythonModels/systems/test_mql.py

@@ -4944,6 +4944,43 @@ class TestMqlSystem:
                 f"{p4_port1_next_orifice_output_spec.alias} does not connect "
                 f"{p4_port1_next_node_alias}.port_4 to {p4_port1_next_orifice_alias}"
             )
+        p4_port1_next_orifice_resistance = self._pnl00r_line_for_node_port(
+            p4_port1_next_orifice_node.alias,
+            "port_3",
+        )
+        p4_port1_next_orifice_resistance_node = other_node3_for_pnl00r(
+            p4_port1_next_orifice_resistance.name,
+            p4_port1_next_orifice_node.alias,
+        )
+        p4_port1_next_orifice_resistance_line_spec = self._pnl0003_spec_for_node_port(
+            p4_port1_next_orifice_resistance_node.alias,
+            "port_2",
+        )
+        p4_port1_next_orifice_resistance_line = self.pnl0003_assembly.lines[
+            p4_port1_next_orifice_resistance_line_spec.alias
+        ]
+        p4_port1_next_orifice_resistance_orifice_alias = (
+            p4_port1_next_orifice_resistance_line_spec.target_component
+            if p4_port1_next_orifice_resistance_line_spec.source_component
+            == p4_port1_next_orifice_resistance_node.alias
+            else p4_port1_next_orifice_resistance_line_spec.source_component
+        )
+        p4_port1_next_orifice_resistance_orifice = (
+            self.pneumatic_assembly.variable_orifices[
+                p4_port1_next_orifice_resistance_orifice_alias
+            ]
+        )
+        p4_port1_far_orifice_direct = self.p4_node_neighborhood(
+            p4_port1_far_node_alias
+        ).port_4
+        if (
+            p4_port1_far_orifice_direct.orifice_alias
+            != p4_port1_next_orifice_resistance_orifice_alias
+        ):
+            raise ValueError(
+                f"{p4_port1_far_node_alias}.port_4 does not use "
+                f"{p4_port1_next_orifice_resistance_orifice_alias}"
+            )
         p4_port3_remote_orifice = self.pneumatic_assembly.variable_orifices[
             p4_port3_remote_neighborhood.port_4.orifice_alias
         ]
@@ -5067,6 +5104,13 @@ class TestMqlSystem:
             raise TypeError(
                 f"{p4_port1_next_orifice_alias} is not an AMESim pneumatic orifice"
             )
+        if not isinstance(
+            p4_port1_next_orifice_resistance_orifice,
+            AmesimPneumaticOrifice,
+        ):
+            raise TypeError(
+                f"{p4_port1_next_orifice_resistance_orifice_alias} is not an AMESim pneumatic orifice"
+            )
         if not isinstance(p4_bridge_primary_chamber, AmesimPneumaticVolume):
             raise TypeError(
                 f"{p4_bridge_primary_chamber_alias} is not an AMESim pneumatic volume"
@@ -5111,6 +5155,16 @@ class TestMqlSystem:
                 p4_port1_next_orifice_line=p4_port1_next_orifice_line,
                 p4_port1_next_orifice_node=p4_port1_next_orifice_node,
                 p4_port1_next_orifice_output_line=p4_port1_next_orifice_output_line,
+                p4_port1_next_orifice_resistance=p4_port1_next_orifice_resistance,
+                p4_port1_next_orifice_resistance_node=(
+                    p4_port1_next_orifice_resistance_node
+                ),
+                p4_port1_next_orifice_resistance_line=(
+                    p4_port1_next_orifice_resistance_line
+                ),
+                p4_port1_next_orifice_resistance_orifice=(
+                    p4_port1_next_orifice_resistance_orifice
+                ),
                 p4_bridge_node=p4_bridge_node,
                 p4_bridge_primary_line=p4_bridge_primary_line,
                 p4_bridge_primary_chamber=p4_bridge_primary_chamber,

PythonModels/systems/test_mql_closure.py

@@ -216,6 +216,10 @@ class TestMqlPn3P4NodeChamberSegmentComponents:
     p4_port1_next_orifice_line: AmesimPnl0003Pipe
     p4_port1_next_orifice_node: TestMqlPneumaticNode3
     p4_port1_next_orifice_output_line: AmesimPnl0001Pipe
+    p4_port1_next_orifice_resistance: AmesimPnl00rPipe
+    p4_port1_next_orifice_resistance_node: TestMqlPneumaticNode3
+    p4_port1_next_orifice_resistance_line: AmesimPnl0003Pipe
+    p4_port1_next_orifice_resistance_orifice: AmesimPneumaticOrifice
     p4_bridge_node: TestMqlPneumaticNode4
     p4_bridge_primary_line: AmesimPnl0001Pipe
     p4_bridge_primary_chamber: AmesimPneumaticVolume
@@ -293,6 +297,8 @@ class TestMqlPn3P4NodeChamberSegmentSnapshot:
     p4_port1_next_orifice_line_port_1: ThermodynamicProperties
     p4_port1_next_orifice_line_port_2: ThermodynamicProperties
     p4_port1_next_orifice_output_line: ThermodynamicProperties
+    p4_port1_next_orifice_resistance_line_port_1: ThermodynamicProperties
+    p4_port1_next_orifice_resistance_line_port_2: ThermodynamicProperties
     p4_bridge_primary_line: ThermodynamicProperties
     p4_bridge_primary_chamber: ThermodynamicProperties
     p4_port1_remote_orifice_line_port_1: ThermodynamicProperties
@@ -334,6 +340,7 @@ class TestMqlPn3P4NodeChamberSegmentSnapshot:
     p4_bridge_balance: TestMqlPneumaticNode4Balance
     p4_port1_remote_orifice_node_balance: TestMqlPneumaticNode3Balance
     p4_port1_next_orifice_node_balance: TestMqlPneumaticNode3Balance
+    p4_port1_next_orifice_resistance_node_balance: TestMqlPneumaticNode3Balance
     p4_port3_remote_balance: TestMqlPneumaticNode4Balance
     p4_port3_far_balance: TestMqlPneumaticNode4Balance
     p4_port3_next_balance: TestMqlPneumaticNode4Balance
@@ -368,6 +375,10 @@ class TestMqlPn3P4NodeChamberSegmentSnapshot:
     p4_port1_next_orifice_node_to_line_flow: float
     p4_port1_next_orifice_line_center_flow: float
     p4_port1_next_orifice_to_output_line_flow: float
+    p4_port1_next_orifice_resistance_node_to_next_flow: float
+    p4_port1_next_orifice_resistance_node_to_line_flow: float
+    p4_port1_next_orifice_resistance_line_center_flow: float
+    p4_port1_next_orifice_resistance_to_p4_flow: float
     p4_bridge_to_port1_next_line_flow: float
     p4_bridge_chamber_to_line_flow: float
     p4_bridge_node_to_primary_line_flow: float
@@ -480,11 +491,12 @@ class TestMqlPn3P4NodeChamberSegmentClosure:
             *self.components.p4_port3_next_resistance_chamber_outlet_line.get_state_vector(),
             *self.components.p4_port1_next_orifice_line.get_state_vector(),
             *self.components.p4_port1_next_orifice_output_line.get_state_vector(),
+            *self.components.p4_port1_next_orifice_resistance_line.get_state_vector(),
         ]
 
     def apply_state_vector(self, values: list[float]) -> None:
-        if len(values) != 102:
-            raise ValueError("PN3/P4 node chamber segment state vector requires one hundred two values")
+        if len(values) != 106:
+            raise ValueError("PN3/P4 node chamber segment state vector requires one hundred six values")
         self.components.inlet_line.set_state_vector(values[:2])
         self.components.volume.set_state_vector(values[2:4])
         self.components.outlet_line.set_state_vector(values[4:6])
@@ -528,7 +540,8 @@ class TestMqlPn3P4NodeChamberSegmentClosure:
         self.components.p4_port3_next_resistance_chamber.set_state_vector(values[92:94])
         self.components.p4_port3_next_resistance_chamber_outlet_line.set_state_vector(values[94:96])
         self.components.p4_port1_next_orifice_line.set_state_vector(values[96:100])
-        self.components.p4_port1_next_orifice_output_line.set_state_vector(values[100:])
+        self.components.p4_port1_next_orifice_output_line.set_state_vector(values[100:102])
+        self.components.p4_port1_next_orifice_resistance_line.set_state_vector(values[102:])
 
     def snapshot(
         self,
@@ -572,6 +585,12 @@ class TestMqlPn3P4NodeChamberSegmentClosure:
         p4_port1_next_orifice_output_line = (
             self.components.p4_port1_next_orifice_output_line.properties()
         )
+        p4_port1_next_orifice_resistance_line_port_1 = (
+            self.components.p4_port1_next_orifice_resistance_line.properties_1()
+        )
+        p4_port1_next_orifice_resistance_line_port_2 = (
+            self.components.p4_port1_next_orifice_resistance_line.properties_2()
+        )
         p4_bridge_primary_line = self.components.p4_bridge_primary_line.properties()
         p4_bridge_primary_chamber = self.components.p4_bridge_primary_chamber.properties()
         p4_port1_remote_orifice_line_port_1 = (
@@ -955,6 +974,14 @@ class TestMqlPn3P4NodeChamberSegmentClosure:
                 orifice=self.components.p4_port3_next_resistance_chamber_outlet_orifice,
             )
         )
+        p4_port1_next_orifice_resistance_node_to_next_flow = (
+            self.components.p4_port1_next_orifice_resistance.mass_flow(
+                port_1_pressure_pa=p4_port1_next_orifice_resistance_line_port_1.p,
+                port_1_temperature_k=p4_port1_next_orifice_resistance_line_port_1.T,
+                port_2_pressure_pa=p4_port1_next_orifice_line_port_1.p,
+                port_2_temperature_k=p4_port1_next_orifice_line_port_1.T,
+            )
+        )
         p4_port1_next_orifice_node_balance = (
             self.components.p4_port1_next_orifice_node.balance(
                 port_2_temperature_k=p4_port1_next_orifice_line_port_1.T,
@@ -967,8 +994,14 @@ class TestMqlPn3P4NodeChamberSegmentClosure:
                 port_1_mass_flow_g_s=(
                     p4_port3_next_resistance_chamber_inlet_node_to_line_flow * 1.0e3
                 ),
-                port_3_enthalpy_flow_w=0.0,
-                port_3_mass_flow_g_s=0.0,
+                port_3_enthalpy_flow_w=self._enthalpy_flow_from_node(
+                    flow_kg_s=-p4_port1_next_orifice_resistance_node_to_next_flow,
+                    node_h=p4_port1_next_orifice_line_port_1.h,
+                    connected_h=p4_port1_next_orifice_resistance_line_port_1.h,
+                ),
+                port_3_mass_flow_g_s=(
+                    -p4_port1_next_orifice_resistance_node_to_next_flow * 1.0e3
+                ),
             )
         )
         p4_port1_next_orifice_node_to_line_flow = (
@@ -982,6 +1015,34 @@ class TestMqlPn3P4NodeChamberSegmentClosure:
             p4_boundary=p4_port1_next_orifice_output_line,
             orifice=self.components.p4_port1_next_orifice,
         )
+        p4_port1_next_orifice_resistance_node_balance = (
+            self.components.p4_port1_next_orifice_resistance_node.balance(
+                port_2_temperature_k=p4_port1_next_orifice_resistance_line_port_1.T,
+                port_2_pressure_pa=p4_port1_next_orifice_resistance_line_port_1.p,
+                port_1_enthalpy_flow_w=self._enthalpy_flow_from_node(
+                    flow_kg_s=p4_port1_next_orifice_resistance_node_to_next_flow,
+                    node_h=p4_port1_next_orifice_resistance_line_port_1.h,
+                    connected_h=p4_port1_next_orifice_line_port_1.h,
+                ),
+                port_1_mass_flow_g_s=(
+                    p4_port1_next_orifice_resistance_node_to_next_flow * 1.0e3
+                ),
+                port_3_enthalpy_flow_w=0.0,
+                port_3_mass_flow_g_s=0.0,
+            )
+        )
+        p4_port1_next_orifice_resistance_node_to_line_flow = (
+            -p4_port1_next_orifice_resistance_node_balance.port_2_mass_flow_g_s
+            * 1.0e-3
+        )
+        p4_port1_next_orifice_resistance_line_center_flow = (
+            self.components.p4_port1_next_orifice_resistance_line.resistance_mass_flow()
+        )
+        p4_port1_next_orifice_resistance_to_p4_flow = self._line_to_p4_flow(
+            line=p4_port1_next_orifice_resistance_line_port_2,
+            p4_boundary=p4_port1_far_primary_line,
+            orifice=self.components.p4_port1_next_orifice_resistance_orifice,
+        )
         p4_port3_next_resistance_node_balance = (
             self.components.p4_port3_next_resistance_node.balance(
                 port_2_temperature_k=p4_port3_next_resistance_node_line_port_1.T,
@@ -1162,8 +1223,14 @@ class TestMqlPn3P4NodeChamberSegmentClosure:
                 connected_h=p4_port1_remote_port1_line.h,
             ),
             port_3_mass_flow_g_s=-p4_port1_far_node_to_line_flow * 1.0e3,
-            port_4_enthalpy_flow_w=0.0,
-            port_4_mass_flow_g_s=0.0,
+            port_4_enthalpy_flow_w=self._enthalpy_flow_from_node(
+                flow_kg_s=p4_port1_next_orifice_resistance_to_p4_flow,
+                node_h=p4_port1_next_orifice_resistance_line_port_2.h,
+                connected_h=p4_port1_far_primary_line.h,
+            ),
+            port_4_mass_flow_g_s=(
+                p4_port1_next_orifice_resistance_to_p4_flow * 1.0e3
+            ),
         )
         p4_port1_far_node_to_primary_line_flow = (
             p4_port1_far_balance.port_2_mass_flow_g_s * 1.0e-3
@@ -1318,6 +1385,12 @@ class TestMqlPn3P4NodeChamberSegmentClosure:
             p4_port1_next_orifice_line_port_1=p4_port1_next_orifice_line_port_1,
             p4_port1_next_orifice_line_port_2=p4_port1_next_orifice_line_port_2,
             p4_port1_next_orifice_output_line=p4_port1_next_orifice_output_line,
+            p4_port1_next_orifice_resistance_line_port_1=(
+                p4_port1_next_orifice_resistance_line_port_1
+            ),
+            p4_port1_next_orifice_resistance_line_port_2=(
+                p4_port1_next_orifice_resistance_line_port_2
+            ),
             p4_bridge_primary_line=p4_bridge_primary_line,
             p4_bridge_primary_chamber=p4_bridge_primary_chamber,
             p4_port1_remote_orifice_line_port_1=p4_port1_remote_orifice_line_port_1,
@@ -1373,6 +1446,9 @@ class TestMqlPn3P4NodeChamberSegmentClosure:
             p4_bridge_balance=p4_bridge_balance,
             p4_port1_remote_orifice_node_balance=p4_port1_remote_orifice_node_balance,
             p4_port1_next_orifice_node_balance=p4_port1_next_orifice_node_balance,
+            p4_port1_next_orifice_resistance_node_balance=(
+                p4_port1_next_orifice_resistance_node_balance
+            ),
             p4_port3_remote_balance=p4_port3_remote_balance,
             p4_port3_far_balance=p4_port3_far_balance,
             p4_port3_next_balance=p4_port3_next_balance,
@@ -1423,6 +1499,18 @@ class TestMqlPn3P4NodeChamberSegmentClosure:
             p4_port1_next_orifice_to_output_line_flow=(
                 p4_port1_next_orifice_to_output_line_flow
             ),
+            p4_port1_next_orifice_resistance_node_to_next_flow=(
+                p4_port1_next_orifice_resistance_node_to_next_flow
+            ),
+            p4_port1_next_orifice_resistance_node_to_line_flow=(
+                p4_port1_next_orifice_resistance_node_to_line_flow
+            ),
+            p4_port1_next_orifice_resistance_line_center_flow=(
+                p4_port1_next_orifice_resistance_line_center_flow
+            ),
+            p4_port1_next_orifice_resistance_to_p4_flow=(
+                p4_port1_next_orifice_resistance_to_p4_flow
+            ),
             p4_bridge_to_port1_next_line_flow=p4_bridge_to_port1_next_line_flow,
             p4_bridge_chamber_to_line_flow=p4_bridge_chamber_to_line_flow,
             p4_bridge_node_to_primary_line_flow=p4_bridge_node_to_primary_line_flow,
@@ -1772,6 +1860,30 @@ class TestMqlPn3P4NodeChamberSegmentClosure:
         p4_port1_next_orifice_output_line.port_2.m_flow = snapshot.p4_port1_next_orifice_to_output_line_flow
         p4_port1_next_orifice_output_line.port_2.h_outflow = snapshot.p4_port1_next_orifice_output_line.h
 
+        p4_port1_next_orifice_resistance = self.components.p4_port1_next_orifice_resistance
+        p4_port1_next_orifice_resistance.port_1.p = snapshot.p4_port1_next_orifice_resistance_line_port_1.p
+        p4_port1_next_orifice_resistance.port_1.m_flow = snapshot.p4_port1_next_orifice_resistance_node_to_next_flow
+        p4_port1_next_orifice_resistance.port_1.h_outflow = snapshot.p4_port1_next_orifice_resistance_line_port_1.h
+        p4_port1_next_orifice_resistance.port_2.p = snapshot.p4_port1_next_orifice_line_port_1.p
+        p4_port1_next_orifice_resistance.port_2.m_flow = -snapshot.p4_port1_next_orifice_resistance_node_to_next_flow
+        p4_port1_next_orifice_resistance.port_2.h_outflow = snapshot.p4_port1_next_orifice_line_port_1.h
+
+        p4_port1_next_orifice_resistance_line = self.components.p4_port1_next_orifice_resistance_line
+        p4_port1_next_orifice_resistance_line.port_1.p = snapshot.p4_port1_next_orifice_resistance_line_port_1.p
+        p4_port1_next_orifice_resistance_line.port_1.m_flow = snapshot.p4_port1_next_orifice_resistance_node_to_line_flow
+        p4_port1_next_orifice_resistance_line.port_1.h_outflow = snapshot.p4_port1_next_orifice_resistance_line_port_1.h
+        p4_port1_next_orifice_resistance_line.port_2.p = snapshot.p4_port1_next_orifice_resistance_line_port_2.p
+        p4_port1_next_orifice_resistance_line.port_2.m_flow = -snapshot.p4_port1_next_orifice_resistance_to_p4_flow
+        p4_port1_next_orifice_resistance_line.port_2.h_outflow = snapshot.p4_port1_next_orifice_resistance_line_port_2.h
+
+        p4_port1_next_orifice_resistance_orifice = self.components.p4_port1_next_orifice_resistance_orifice
+        p4_port1_next_orifice_resistance_orifice.port_a.p = snapshot.p4_port1_next_orifice_resistance_line_port_2.p
+        p4_port1_next_orifice_resistance_orifice.port_a.m_flow = snapshot.p4_port1_next_orifice_resistance_to_p4_flow
+        p4_port1_next_orifice_resistance_orifice.port_a.h_outflow = snapshot.p4_port1_next_orifice_resistance_line_port_2.h
+        p4_port1_next_orifice_resistance_orifice.port_b.p = snapshot.p4_port1_far_primary_line.p
+        p4_port1_next_orifice_resistance_orifice.port_b.m_flow = -snapshot.p4_port1_next_orifice_resistance_to_p4_flow
+        p4_port1_next_orifice_resistance_orifice.port_b.h_outflow = snapshot.p4_port1_far_primary_line.h
+
         p4_bridge_primary_line = self.components.p4_bridge_primary_line
         p4_bridge_primary_line.port_1.p = snapshot.p4_bridge_primary_chamber.p
         p4_bridge_primary_line.port_1.m_flow = snapshot.p4_bridge_chamber_to_line_flow
@@ -2472,6 +2584,15 @@ class TestMqlPn3P4NodeChamberSegmentClosure:
                 connected_h_2=snapshot.p4_port1_next_orifice_line_port_2.h,
             )
         )
+        (
+            p4_port1_next_orifice_resistance_derivative_1,
+            p4_port1_next_orifice_resistance_derivative_2,
+        ) = self.components.p4_port1_next_orifice_resistance_line.derivatives_from_connections(
+            port_1_m_flow=snapshot.p4_port1_next_orifice_resistance_node_to_line_flow,
+            connected_h_1=snapshot.p4_port1_next_orifice_resistance_line_port_1.h,
+            port_2_m_flow=-snapshot.p4_port1_next_orifice_resistance_to_p4_flow,
+            connected_h_2=snapshot.p4_port1_far_primary_line.h,
+        )
         return [
             *inlet_derivative.as_vector(),
             *chamber_derivative.as_vector(),
@@ -2524,6 +2645,8 @@ class TestMqlPn3P4NodeChamberSegmentClosure:
             *p4_port1_next_orifice_derivative_1.as_vector(),
             *p4_port1_next_orifice_derivative_2.as_vector(),
             *p4_port1_next_orifice_output_derivative.as_vector(),
+            *p4_port1_next_orifice_resistance_derivative_1.as_vector(),
+            *p4_port1_next_orifice_resistance_derivative_2.as_vector(),
         ]
 
 

tests/test_test_mql_pnl0001_segment.py

@@ -472,8 +472,24 @@ class TestMqlPn3P4NodeChamberSegmentTests(unittest.TestCase):
             closure.components.p4_port1_next_orifice_output_line.name,
             "pneumatic_79",
         )
-        self.assertEqual(len(closure.initial_state_vector()), 102)
-        self.assertEqual(len(rhs), 102)
+        self.assertEqual(
+            closure.components.p4_port1_next_orifice_resistance.name,
+            "pneumatic_107",
+        )
+        self.assertEqual(
+            closure.components.p4_port1_next_orifice_resistance_node.alias,
+            "pn_node3_11",
+        )
+        self.assertEqual(
+            closure.components.p4_port1_next_orifice_resistance_line.name,
+            "pneumatic_76",
+        )
+        self.assertEqual(
+            closure.components.p4_port1_next_orifice_resistance_orifice.name,
+            "pn_morifice_15",
+        )
+        self.assertEqual(len(closure.initial_state_vector()), 106)
+        self.assertEqual(len(rhs), 106)
         self.assertAlmostEqual(
             snapshot.p4_balance.pressure_pa,
             snapshot.p4_primary_line.p,
@@ -569,6 +585,22 @@ class TestMqlPn3P4NodeChamberSegmentTests(unittest.TestCase):
             closure.components.p4_port1_next_orifice.name,
             "pn_morifice_11",
         )
+        self.assertEqual(
+            closure.components.p4_port1_next_orifice_resistance.name,
+            self.system._pnl00r_line_for_node_port("pn_node3_12", "port_3").name,
+        )
+        self.assertEqual(
+            closure.components.p4_port1_next_orifice_resistance_node.alias,
+            "pn_node3_11",
+        )
+        self.assertEqual(
+            closure.components.p4_port1_next_orifice_resistance_line.name,
+            self.system._pnl0003_line_for_node_port("pn_node3_11", "port_2").name,
+        )
+        self.assertEqual(
+            closure.components.p4_port1_next_orifice_resistance_orifice.name,
+            "pn_morifice_15",
+        )
         self.assertEqual(
             closure.components.p4_bridge_node.alias,
             port1_next_port1.remote_node_alias,
@@ -809,7 +841,8 @@ class TestMqlPn3P4NodeChamberSegmentTests(unittest.TestCase):
         self.assertAlmostEqual(
             snapshot.p4_port1_far_node_to_primary_line_flow
             + snapshot.p4_port1_far_node_to_line_flow
-            + snapshot.p4_port1_far_to_next_line_flow,
+            + snapshot.p4_port1_far_to_next_line_flow
+            - snapshot.p4_port1_next_orifice_resistance_to_p4_flow,
             0.0,
             delta=1.0e-12,
         )
@@ -903,7 +936,14 @@ class TestMqlPn3P4NodeChamberSegmentTests(unittest.TestCase):
         )
         self.assertAlmostEqual(
             snapshot.p4_port1_next_orifice_node_to_line_flow
-            + snapshot.p4_port3_next_resistance_chamber_inlet_node_to_line_flow,
+            + snapshot.p4_port3_next_resistance_chamber_inlet_node_to_line_flow
+            - snapshot.p4_port1_next_orifice_resistance_node_to_next_flow,
+            0.0,
+            delta=1.0e-12,
+        )
+        self.assertAlmostEqual(
+            snapshot.p4_port1_next_orifice_resistance_node_to_line_flow
+            + snapshot.p4_port1_next_orifice_resistance_node_to_next_flow,
             0.0,
             delta=1.0e-12,
         )
@@ -942,14 +982,23 @@ class TestMqlPn3P4NodeChamberSegmentTests(unittest.TestCase):
             ),
             delta=1.0e-12,
         )
-        mass_derivative_sum = sum(rhs[index] for index in range(0, 102, 2))
+        p4_port1_next_orifice_resistance_line_mass_sum = rhs[102] + rhs[104]
+        self.assertAlmostEqual(
+            p4_port1_next_orifice_resistance_line_mass_sum,
+            (
+                snapshot.p4_port1_next_orifice_resistance_node_to_line_flow
+                - snapshot.p4_port1_next_orifice_resistance_to_p4_flow
+            ),
+            delta=1.0e-12,
+        )
+        mass_derivative_sum = sum(rhs[index] for index in range(0, 106, 2))
         self.assertAlmostEqual(
             mass_derivative_sum,
             0.0,
             delta=1.0e-12,
         )
 
-    def test_simulates_one_hundred_two_state_pn3_p4_node_chamber_segment(self) -> None:
+    def test_simulates_one_hundred_six_state_pn3_p4_node_chamber_segment(self) -> None:
         solution = self.system.simulate_pn3_p4_node_chamber_segment_from_spec(
             self.spec,
             inlet_node_pressure_pa=15.31e6,
@@ -964,8 +1013,8 @@ class TestMqlPn3P4NodeChamberSegmentTests(unittest.TestCase):
 
         self.assertTrue(solution.success)
         self.assertEqual(len(solution.t), 3)
-        self.assertEqual(len(solution.y), 102)
-        self.assertEqual([len(row) for row in solution.y], [3] * 102)
+        self.assertEqual(len(solution.y), 106)
+        self.assertEqual([len(row) for row in solution.y], [3] * 106)
 
 
 if __name__ == "__main__":