Establishment of test conditions in the RHYFL-X facility

While current high enthalpy facilities are capable of generating the enthalpies associated with very high speed atmospheric flight, they are incapable of generating the large total pressures needed for full flow similarity. For accurate aerodynamic, heating, and combustion testing in ground-based facilities, it is desirable to increase their total pressure simulation capabilities. This paper continues the simulation study for the proposed conversion of RHYFL, originally designed to be a shock tube, into an expansion tunnel. In particular, we focus on the design of a suitable nozzle shape and on the details of the nozzle starting processes when supplied with a short duration pulse of test gas. To check whether steady flow conditions can be established in scramjet models, a ducted flow experiment has been conducted in a large prototype facility, X3. Flow measurements of heat transfer and static pressure indicate that useful test flows can indeed be established.