完善 PNL00R 摩擦模型与八路回归

app/simulation/components/amesim/flow/pipes.py

@@ -54,6 +54,22 @@ class Pnl0001DerivativeLinearization:
 
 _MAX_REPORTED_FRICTION_FACTOR = 64_000_000.0
 
+# ``pn2pipefr`` blends the laminar and turbulent friction branches over a
+# much wider Reynolds range than the former hard 2300..4000 interpolation.
+# These constants are a uniform-Re least-squares fit to the unchanged
+# Simcenter Amesim 2404 test_mql result for PNL00R/PNL0001/PNL0003 at both
+# rr=0.045/14 and rr=0.045/20.  The shifted Hill exponent is greater than 2,
+# so its zero-valued join to the laminar branch is C2 continuous.
+_PN2PIPEFR_TRANSITION_START_REYNOLDS = 89.96829989
+_PN2PIPEFR_TRANSITION_SCALE_REYNOLDS = 2741.96700831
+_PN2PIPEFR_TRANSITION_SHARPNESS = 8.37293695
+
+# PNL00R keeps the exact closed-form laminar solve where the fitted
+# transition contribution is below four parts per million.  Extending this
+# shortcut to Re=2300 bypassed the real AMESim transition and introduced a
+# solver-visible branch point.
+_PN2PIPEFR_ANALYTIC_LAMINAR_MAX_REYNOLDS = 1000.0
+
 
 def _reported_friction_factor(value: float) -> float:
     return min(float(value), _MAX_REPORTED_FRICTION_FACTOR)
@@ -75,8 +91,8 @@ class AmesimPnl00r(AlgebraicComponent):
     """AMESim PNL00R pneumatic pipe friction resistance.
 
     The public model exposes the AMESim PNL00R catalog/XML contract and uses
-    an auditable Darcy-Weisbach resistance with Reynolds/roughness-dependent
-    friction. Exact `pn2pipefr_` parity is left for the later model tuning pass.
+    the `pn2pipefr` compressible gas relation with a Reynolds/roughness-
+    dependent equivalent flow coefficient.
     """
 
     MODEL_TYPE = "amesim_pnl00r"
@@ -244,7 +260,7 @@ class AmesimPnl00r(AlgebraicComponent):
         if reynolds_number <= 0.0:
             return 64_000_000.0
         laminar = 64.0 / reynolds_number
-        if reynolds_number <= 2300.0:
+        if reynolds_number <= _PN2PIPEFR_TRANSITION_START_REYNOLDS:
             return laminar
 
         # pn2pipefr does not apply the fully rough correction at every
@@ -274,10 +290,13 @@ class AmesimPnl00r(AlgebraicComponent):
             turbulent = smooth_turbulent + roughness_weight * (
                 fully_rough - smooth_turbulent
             )
-        if reynolds_number >= 4000.0:
-            return turbulent
-        fraction = (reynolds_number - 2300.0) / 1700.0
-        return laminar + fraction**0.58 * (turbulent - laminar)
+        transition_coordinate = (
+            (reynolds_number - _PN2PIPEFR_TRANSITION_START_REYNOLDS)
+            / _PN2PIPEFR_TRANSITION_SCALE_REYNOLDS
+        )
+        transition_power = transition_coordinate**_PN2PIPEFR_TRANSITION_SHARPNESS
+        transition_weight = transition_power / (1.0 + transition_power)
+        return laminar + transition_weight * (turbulent - laminar)
 
     def darcy_pressure_drop(
         self,
@@ -329,13 +348,17 @@ class AmesimPnl00r(AlgebraicComponent):
         if isclose(p_1, p_2, rel_tol=0.0, abs_tol=1.0e-8):
             return 0.0
         pressure_difference = p_1 - p_2
-        upstream_pressure = max(p_1, p_2, 1.0)
-        upstream_temperature = self._port_temperature("port_1" if pressure_difference > 0.0 else "port_2")
-        density = max(self.medium.density(upstream_pressure, upstream_temperature), 1.0e-12)
-        magnitude = self._mass_flow_for_pressure_drop(
-            abs(pressure_difference),
-            density=density,
-            temperature=upstream_temperature,
+        upstream_temperature = self._port_temperature(
+            "port_1" if pressure_difference > 0.0 else "port_2"
+        )
+        magnitude = AmesimPnl0001._one_way_pn2pipefr_mass_flow(
+            self,
+            upstream_pressure=max(p_1, p_2),
+            downstream_pressure=min(p_1, p_2),
+            upstream_temperature=upstream_temperature,
+            resistance_length=self.le,
+            max_iterations=64,
+            analytic_laminar=True,
         )
         return magnitude if pressure_difference > 0.0 else -magnitude
 
@@ -347,17 +370,19 @@ class AmesimPnl00r(AlgebraicComponent):
         )
         density = max(self.medium.density(upstream_pressure, upstream_temperature), 1.0e-12)
         reynolds = self.reynolds_number(m_flow, upstream_temperature)
+        friction = self.friction_factor(reynolds)
+        flow_coefficient = sqrt(self.diam / (self.le * friction))
         velocity = m_flow / (density * self.area)
         cm = (
             abs(m_flow)
             * sqrt(upstream_temperature)
-            / max(self.area * upstream_pressure, 1.0e-18)
+            / max(flow_coefficient * self.area * upstream_pressure, 1.0e-18)
         )
         return {
             "re": reynolds,
             "cm": cm,
             "v": velocity,
-            "ff": _reported_friction_factor(self.friction_factor(reynolds)),
+            "ff": _reported_friction_factor(friction),
         }
 
     def pressure_flow_equation_values(self) -> tuple[float, ...]:
@@ -754,6 +779,8 @@ class AmesimPnl0001(ThermodynamicVolumeComponent):
         downstream_pressure: float,
         upstream_temperature: float,
         resistance_length: float,
+        max_iterations: int = 16,
+        analytic_laminar: bool = False,
     ) -> float:
         """AMESim pn2pipefr-style compressible friction flow."""
 
@@ -824,6 +851,18 @@ class AmesimPnl0001(ThermodynamicVolumeComponent):
                 value *= tanh(max(smoothing_argument, 0.0))
             return value
 
+        if analytic_laminar:
+            flow_parameter = mass_flow_parameter(pressure_ratio)
+            viscosity = self._dynamic_viscosity(T_up)
+            laminar_mass_flow = (
+                self.area * p_up * flow_parameter
+            ) ** 2 / (16.0 * pi * viscosity * resistance_length * T_up)
+            if (
+                self.reynolds_number(laminar_mass_flow, T_up)
+                <= _PN2PIPEFR_ANALYTIC_LAMINAR_MAX_REYNOLDS
+            ):
+                return laminar_mass_flow
+
         def target_flow(mass_flow: float) -> float:
             reynolds = self.reynolds_number(mass_flow, T_up)
             friction = self.friction_factor(reynolds)
@@ -846,7 +885,7 @@ class AmesimPnl0001(ThermodynamicVolumeComponent):
             * mass_flow_parameter(pressure_ratio)
             / sqrt(T_up)
         )
-        for _iteration in range(16):
+        for _iteration in range(max_iterations):
             next_magnitude = target_flow(magnitude)
             if abs(next_magnitude - magnitude) <= max(
                 1.0e-12,