Shock Tube Instrumentation Techniques for Study of Hypervelocity Entry Problems

Shock tube instrumentation techniques developed for the study of convective heat transfer and the radiative properties of high temperature gases at conditions simulating hypervelocity entry into planetary atmospheres are described. An electrically heated helium driven shock tube is used; measurement methods suitable for conventional shock tubes must be modified before they can be used in the hypervelocity shock tube. Extremely high shock velocities necessary for proper simulation are associated with very short test times imposing requirements for fast response instrumentation systems. Methods for evaluating test gas quality are illustrated. Techniques described have been applied to several studies; typical results are shown and instrumentation requirements for the extension of aerothermodynamic investigation in the hypervelocity regime are outlined.