UNSTART PHENOMENON DUE TO THERMAL CHOKE IN SCRAMJET MODULE

Growth mechanism of thermally choked flow was investigated by hydrogen injection into scramjet module in the Mach 2 preheated wind tunnel. Experiments were performed in variation of fuel equivalence ratio and its effect on air-intake were examined. In high equivalence ratio, unstart transition due to thermal choke appeared in terms of discontinuity of static pressure and total temperature and the effect on air-intake was remarkable. The transition was performed instantly and the propagation speed was fairly high. The mechanism is not cleared yet but some possibilities are discussed.