Engine working

Interfaces/Port.cs

@@ -1,21 +1,14 @@
 namespace FluidSim.Interfaces
 {
-    /// <summary>
-    /// A fluid port that belongs to a component. The solver writes mass flow,
-    /// enthalpy, etc. here, and reads pressure, density, etc.
-    /// </summary>
     public class Port
     {
-        // Set by the solver during coupling resolution
         public double MassFlowRate;         // kg/s, positive INTO the component that owns this port
-        public double SpecificEnthalpy;     // J/kg, enthalpy of the fluid crossing the port (inflow direction)
-
-        // Set by the owning component after integration to reflect its current state
+        public double SpecificEnthalpy;     // J/kg
         public double Pressure;             // Pa
         public double Density;              // kg/m³
         public double Temperature;          // K
+        public double AirFraction;          // mass fraction of air (0 = exhaust, 1 = air)
 
-        // Link back to owner (optional, but handy for debugging)
         public object? Owner { get; set; }
 
         public Port()
@@ -25,6 +18,7 @@
             Pressure = 101325.0;
             Density = 1.225;
             Temperature = 300.0;
+            AirFraction = 1.0;   // default fresh air
         }
     }
 }