THERMAL CHOKING IN 2-DIMENSIONAL EXPANSION FLOWS

Two-dimensional supersonic flows with heat addition from given interna l sources and/or nonequilibrium condensation are considered. The criti cal amount of heat necessary to thermally choke the flow is defined at any point in the flow field, and the necessary and sufficient conditi ons for thermal choking are identified from the singularities of the e quations of motion along streamlines. In particular, for any practical purposes, it is shown that the flow Mach number reaches unity at any point where the heat added to the flow along the streamline passing th rough that point reaches the critical value. Thermally choked flows ar e then identified as those flows where the critical heat along streaml ines is exceeded leading to embedded oblique shock waves with a local subsonic Row field downstream.