Ground-Based Testing of The Hyshot II Combustor Using OH Chemiluminescence

Abstract

A series of experiments has been carried out in the HEG reflected-shock wind tunnel to further investigate the combustion characteristics of the HyShot II scramjet configuration. Both steady and unsteady combustion behaviours, induced by varying the equivalence ration between 0.35 and 1.1, were explored. By employing high-speed Schlieren and OH visualization, together with surface-mounted pressure transducers, links between the flow and the combustion features could be drawn. In particular, it is found that the transient shock structures signaling the onset of unstart for large equivalence ratios take the form of an upstream-propagating shock train, and are induced by thermal choking rather than boundary-layer separation. Dpending on the equivalence ratio, however, large-scale flow separation is subsequently observed to develop as the shock system moves upstreaam