Fixed handling of explicit reaction orders for some reactions

For reactions with unity reactant stoichiometric coefficients, explicit values
for the forward reaction order were being ignored while setting up the
StoichManager.

Added a few tests that confirm that these rates are being calculated correctly.

include/cantera/kinetics/StoichManager.h

@@ -827,8 +827,9 @@ class StoichManagerN
         m_n[rxn] = k.size();
         bool frac = false;
         for (size_t n = 0; n < stoich.size(); n++) {
-            if (stoich[n] != 1.0) {
+            if (stoich[n] != 1.0 || order[n] != 1.0) {
                 frac = true;
+                break;
             }
         }
         if (frac) {

test/python/runTests.py

@@ -20,6 +20,7 @@
     loader = unittest.TestLoader()
     runner = unittest.TextTestRunner(verbosity=2)
     suite = loader.loadTestsFromName('testSolution')
+    suite = loader.loadTestsFromName('testKinetics')
     suite.addTests(loader.loadTestsFromName('testPureFluid'))
     suite.addTests(loader.loadTestsFromName('testEquilibrium'))
     suite.addTests(loader.loadTestsFromName('testReactors'))

test/python/testKinetics.py

@@ -0,0 +1,40 @@
+import utilities
+import Cantera as ct
+
+class ExplicitForwardOrderTest(utilities.CanteraTest):
+    def setUp(self):
+        self.gas = ct.IdealGasMix('../data/explicit-forward-order.xml')
+        self.gas.set(T=800, P=101325, X=[0.01, 0.90, 0.02, 0.03, 0.04])
+
+    def test_irreversibility(self):
+        # Reactions are irreversible
+        Rr = self.gas.revRateConstants()
+        self.assertEqual(Rr[0], 0.0)
+        self.assertEqual(Rr[1], 0.0)
+
+    def test_rateConstants(self):
+        # species order: [H, AR, R1A, R1B, P1]
+
+        C = self.gas.moleFractions() * self.gas.molarDensity()
+        Rf = self.gas.fwdRatesOfProgress()
+        kf = self.gas.fwdRateConstants()
+        self.assertNear(Rf[0], kf[0] * C[2]**1.5 * C[3]**0.5)
+        self.assertNear(Rf[1], kf[1] * C[0]**1.0 * C[4]**0.2)
+
+    def test_ratio1(self):
+        rop1 = self.gas.fwdRatesOfProgress()
+        # Double concentration of H and R1A
+        self.gas.set(T=800, P=101325, X=[0.02, 0.87, 0.04, 0.03, 0.04])
+        rop2 = self.gas.fwdRatesOfProgress()
+        ratio = rop2/rop1
+        self.assertNear(ratio[0], 2**1.5) # order of R1A is 1.5
+        self.assertNear(ratio[1], 2**1.0) # order of H is 1.0
+
+    def test_ratio2(self):
+        rop1 = self.gas.fwdRatesOfProgress()
+        # Double concentration of P1 and R1B
+        self.gas.set(T=800, P=101325, X=[0.01, 0.83, 0.02, 0.06, 0.08])
+        rop2 = self.gas.fwdRatesOfProgress()
+        ratio = rop2/rop1
+        self.assertNear(ratio[0], 2**0.5) # order of R1B is 0.5
+        self.assertNear(ratio[1], 2**0.2) # order of P1 is 1.0