补充test_mql PNVO焓流诊断与系数校正

PythonModels/core/peng_robinson.py

@@ -1,7 +1,7 @@
 from __future__ import annotations
 
 from dataclasses import dataclass
-from math import acos, cos, isfinite, pi, sqrt
+from math import acos, cos, isfinite, log, pi, sqrt
 
 UNIVERSAL_GAS_CONSTANT = 8.31446261815324
 
@@ -10,9 +10,8 @@ UNIVERSAL_GAS_CONSTANT = 8.31446261815324
 class PengRobinsonFluid:
     """Pure-fluid Peng-Robinson equation-of-state helper.
 
-    The class intentionally covers the equation-of-state layer first: pressure,
-    compressibility factor, molar volume, and density. Caloric departure
-    properties are left out until the test_mql energy equations need them.
+    The class covers the equation-of-state layer plus the enthalpy departure
+    needed to compare AMESim pneumatic ``pn2hpti`` reference enthalpy flows.
     """
 
     name: str
@@ -50,9 +49,23 @@ class PengRobinsonFluid:
         reduced_temperature = temperature / self.critical_temperature
         return (1.0 + self.kappa * (1.0 - sqrt(reduced_temperature))) ** 2.0
 
+    def alpha_temperature_derivative(self, temperature: float) -> float:
+        self._validate_temperature(temperature)
+        reduced_temperature = temperature / self.critical_temperature
+        sqrt_reduced_temperature = sqrt(reduced_temperature)
+        alpha_base = 1.0 + self.kappa * (1.0 - sqrt_reduced_temperature)
+        return -(
+            alpha_base
+            * self.kappa
+            / (self.critical_temperature * sqrt_reduced_temperature)
+        )
+
     def attractive_parameter(self, temperature: float) -> float:
         return self.a_parameter * self.alpha(temperature)
 
+    def attractive_parameter_temperature_derivative(self, temperature: float) -> float:
+        return self.a_parameter * self.alpha_temperature_derivative(temperature)
+
     def pressure_from_molar_volume(self, temperature: float, molar_volume: float) -> float:
         self._validate_temperature(temperature)
         if molar_volume <= self.b_parameter:
@@ -121,6 +134,35 @@ class PengRobinsonFluid:
     ) -> float:
         return self.molar_mass / self.molar_volume(pressure, temperature, phase=phase)
 
+    def residual_specific_enthalpy(
+        self,
+        pressure: float,
+        temperature: float,
+        phase: str = "vapor",
+    ) -> float:
+        """Return Peng-Robinson enthalpy departure from ideal gas, J/kg."""
+        self._validate_pressure_temperature(pressure, temperature)
+        z = self.compressibility_factor(pressure, temperature, phase=phase)
+        _, B = self.reduced_parameters(pressure, temperature)
+        b = self.b_parameter
+        attractive = self.attractive_parameter(temperature)
+        d_attractive_d_temperature = (
+            self.attractive_parameter_temperature_derivative(temperature)
+        )
+        log_argument = (z + (1.0 + sqrt(2.0)) * B) / (
+            z + (1.0 - sqrt(2.0)) * B
+        )
+        residual_molar_enthalpy = (
+            UNIVERSAL_GAS_CONSTANT * temperature * (z - 1.0)
+            + (
+                temperature * d_attractive_d_temperature
+                - attractive
+            )
+            * log(log_argument)
+            / (2.0 * sqrt(2.0) * b)
+        )
+        return residual_molar_enthalpy / self.molar_mass
+
     @staticmethod
     def _validate_temperature(temperature: float) -> None:
         if temperature <= 0.0: