Test molar enthalpy for IdealSolidSolnPhas

decaluwe · decaluwe · commit f09de9901393 · 2021-08-19T14:00:07.000-06:00
- Test that `enthalpy_mole = sum(X_k * h_k)` for `IdealSolidSolnPhase`
class, where `X_k` is mole fraction and `h_k` partial molar enthalpy.
- Also test the pressure independence of this equality, by verifying at
pressures 1 atm and 2 atm.
diff --git a/test/thermo/thermoFromYaml.cpp b/test/thermo/thermoFromYaml.cpp
@@ -383,6 +383,28 @@ TEST(ThermoFromYaml, IdealSolidSolnPhase)
     EXPECT_NEAR(thermo->density(), 10.1787080, 1e-6);
     EXPECT_NEAR(thermo->enthalpy_mass(), -15642788.8547624, 1e-4);
     EXPECT_NEAR(thermo->gibbs_mole(), -313642312.7114608, 1e-4);
+
+    // Test that molar enthalpy equals sum(h_k*X_k). Test first at default 
+    // pressure:
+    double h_avg = 0;
+    size_t N = thermo->nSpecies();
+    vector_fp X_k(N);
+    vector_fp h_k(N);
+    thermo->getMoleFractions(X_k.data());
+    thermo->getPartialMolarEnthalpies(h_k.data());
+    for (size_t k = 0; k < N; k++) {
+        h_avg += X_k[k]*h_k[k];
+    }
+    EXPECT_NEAR(thermo->enthalpy_mole(), h_avg, 1e-6);
+
+    // Now test the pressure dependence, by repeating at 2 atm:
+    thermo->setState_TP(298, 2*OneAtm);
+    thermo->getPartialMolarEnthalpies(h_k.data());
+    h_avg = 0;
+    for (size_t k = 0; k < N; k++) {
+        h_avg += X_k[k]*h_k[k];
+    }
+    EXPECT_NEAR(thermo->enthalpy_mole(), h_avg, 1e-6);
 }
 
 TEST(ThermoFromYaml, Lattice)
