improved python test and formatting changes to doc strings

Cantera · Mar 11, 2024 · 64df109 · 64df109
1 parent bc50dd7
commit 64df109
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Showing 2 changed files with 21 additions and 8 deletions.
diff --git a/include/cantera/thermo/PengRobinson.h b/include/cantera/thermo/PengRobinson.h
@@ -177,10 +177,10 @@ class PengRobinson : public MixtureFugacityTP
     /*!
      * @return
      *   Returns an AnyMap containing the following key names and values:
-     *   - "aAlpha_mix": The value of m_aAlpha_mix
-     *   - "b_mix": The value of the m_b
-     *   - "daAlpha_dT": The value returned by the daAlpha_dT() method
-     *   - "d2aAlpha_dT2": The value returned by the d2aAlpha_dT2() method
+     *   - `aAlpha_mix`: The value of #m_aAlpha_mix
+     *   - `b_mix`: The value of the #m_b
+     *   - `daAlpha_dT`: The value returned by the daAlpha_dT() method
+     *   - `d2aAlpha_dT2`: The value returned by the d2aAlpha_dT2() method
      */
     AnyMap getAuxiliaryData() override;
 

diff --git a/test/python/test_thermo.py b/test/python/test_thermo.py
@@ -969,16 +969,29 @@ def test_add_species_duplicate(self):
         with self.assertRaisesRegex(ct.CanteraError, 'already contains'):
             self.phase.add_species(species)
 
-
     def test_auxiliary_data(self):
         """
-        Should get back a dictionary with 4 keys present when calling the auxiliary_data
-        property for the Peng-Robinson thermo phase.
+        This test checks that the values of `aAlpha_mix` and `b_mix` should, when
+        used in the Peng-Robinson equation of state expression, yield the same
+        pressure as the pressure that was set for the thermodynamic state.
         """
         gas = ct.Solution('co2_PR_example.yaml', 'CO2-PR')
         gas.TPX = 300, 101325, 'H2:1.0'
         params = gas.auxiliary_data
-        self.assertEqual(len(params), 4)
+
+        # Get the Peng-Robinson equation of state parameters
+        aAlpha_mix = params['aAlpha_mix']
+        b_mix = params['b_mix']
+
+        molar_volume = 1.0 / gas.density_mole
+        # Evaluate the pressure using the Peng-Robinson equation of state
+        # parameters
+        evaluated_pressure = (
+            ct.gas_constant * gas.T / (molar_volume - b_mix) -
+            aAlpha_mix / (molar_volume ** 2 + 2 * b_mix * molar_volume - b_mix ** 2)
+        )
+
+        assert abs(gas.P - evaluated_pressure) < 1e-6
 
 class TestThermo(utilities.CanteraTest):
     def setUp(self):