Scramjet Combustor: Rayleigh Flow & Thermal Choking

A scramjet burns fuel in air that is still moving faster than sound, which makes the combustor one of the hardest parts of the engine to design: heat added to a supersonic flow in a fixed-area duct obeys Rayleigh-flow theory, and that theory says heat can only ever push the Mach number down toward 1, never up. This simulator solves the real Rayleigh relation T0/T0* = (γ+1)M²[2+(γ-1)M²]/(1+γM²)² pointwise along a 3D combustor duct, animating a supersonic airstream that visibly decelerates and heats as fuel-heat is added. Push the heat-addition slider past the duct's thermal-choking limit and the exit Mach number pins at 1 exactly where the physics says it must — triggering the shock train and inlet-unstart behaviour that real scramjet designers spend their careers avoiding.