[Reactor] Add flow-device-specific methods for setting coefficients

include/cantera/zeroD/FlowDevice.h

@@ -77,7 +77,9 @@ public:
         return *m_out;
     }
 
-    //! set parameters
+    //! set parameters. Generic function used only in the Matlab interface. From
+    //! Python or C++, device-specific functions like Valve::setPressureCoeff
+    //! should be used instead.
     virtual void setParameters(int n, doublereal* coeffs) {
         m_coeffs.resize(n);
         std::copy(coeffs, coeffs + n, m_coeffs.begin());

include/cantera/zeroD/flowControllers.h

@@ -57,6 +57,16 @@ public:
         m_master = master;
     }
 
+    //! Set the proportionality constant between pressure drop and mass flow
+    //! rate
+    /*!
+     * *c* has units of kg/s/Pa. The mass flow rate is computed as:
+     * \f[\dot{m} = \dot{m}_{master} + c \Delta P \f]
+     */
+    void setPressureCoeff(double c) {
+        m_coeffs = {c};
+    }
+
     virtual void updateMassFlowRate(doublereal time) {
         if (!ready()) {
             throw CanteraError("PressureController::updateMassFlowRate",
@@ -90,6 +100,16 @@ public:
         return FlowDevice::ready() && (m_coeffs.size() == 1 || m_func);
     }
 
+    //! Set the proportionality constant between pressure drop and mass flow
+    //! rate
+    /*!
+     * *c* has units of kg/s/Pa. The mass flow rate is computed as:
+     * \f[\dot{m} = c \Delta P \f]
+     */
+    void setPressureCoeff(double c) {
+        m_coeffs = {c};
+    }
+
     /// Compute the currrent mass flow rate, based on the pressure difference.
     virtual void updateMassFlowRate(doublereal time) {
         if (!ready()) {

interfaces/cython/cantera/_cantera.pxd

@@ -536,16 +536,17 @@ cdef extern from "cantera/zeroD/flowControllers.h":
         double massFlowRate(double) except +
         cbool install(CxxReactorBase&, CxxReactorBase&) except +
         void setFunction(CxxFunc1*)
-        void setParameters(int, double*)
 
     cdef cppclass CxxMassFlowController "Cantera::MassFlowController" (CxxFlowDevice):
         CxxMassFlowController()
 
     cdef cppclass CxxValve "Cantera::Valve" (CxxFlowDevice):
+        void setPressureCoeff(double)
         CxxValve()
 
     cdef cppclass CxxPressureController "Cantera::PressureController" (CxxFlowDevice):
         CxxPressureController()
+        void setPressureCoeff(double)
         void setMaster(CxxFlowDevice*)
 
 

interfaces/cython/cantera/reactor.pyx

@@ -739,11 +739,10 @@ cdef class Valve(FlowDevice):
         >>> V.set_valve_coeff(1e-4)
         >>> V.set_valve_coeff(lambda dP: (1e-5 * dP)**2)
         """
-        cdef double kv
         cdef Func1 f
         if isinstance(k, _numbers.Real):
             kv = k
-            self.dev.setParameters(1, &kv)
+            (<CxxValve*>self.dev).setPressureCoeff(k)
             return
 
         if isinstance(k, Func1):
@@ -782,7 +781,7 @@ cdef class PressureController(FlowDevice):
         Set the proportionality constant *k* [kg/s/Pa] between the pressure
         drop and the mass flow rate.
         """
-        self.dev.setParameters(1, &k)
+        (<CxxPressureController*>self.dev).setPressureCoeff(k)
 
     def set_master(self, FlowDevice d):
         """

samples/cxx/combustor/combustor.cpp

@@ -92,7 +92,7 @@ void runexample()
     Valve v;
     v.install(combustor, exhaust);
     double Kv = 1.0;
-    v.setParameters(1, &Kv);
+    v.setPressureCoeff(Kv);
 
     // the simulation only contains one reactor
     ReactorNet sim;