American Institute of Aeronautics and Astronautics Inc, AIAA
Fully published paper
The development of scramjet technology using continuos facilities is limited at present to flight Mach numbers less than 8, however, by using impulse facilities, the envelop of test conditions may be extended up to orbital velocity. One of the perceived difficulties with using impulse facilities for aerothermodynamic development is that the test period which is available is insufficient to reach steady state conditions. This paper sets out to address this issue by first discussing time constants of different aerothermodynamic properties. It is shown that provided large regions of recirculation do not exist, then sufficient time exists for the boundary layer and the combustion process to reach a steady state. The paper then proceeds to present the techniques and instrumentation that has been developed for impulse facilities to measure aerothermodynamic properties during the limited test time. Experimental results are also presented which show that phenomena which are observed in continuos facilities in scramjet experiments are also observed in impulse facilities. These experimental results are also used to highlight some of the important design issues which must be addressed if scramjets are to operate in the hypervelocity regime.