Experiments in a Combustion-Driven Shock Tube with an Area Change

Shock tubes are versatile and useful tools for studying high temperature gas dynamics and the production of hypervelocity flows. High shock speeds are desirable for creating higher enthalpy, pressure, and temperature in the test gas which makes the study of thermo-chemical effects on fluid dynamics possible. Independent of construction and operational cost, free-piston drivers, such as the one used in the T5 facility at Caltech, give the best performance [3]. The high operational cost and long turnaround time of such a facility make a more economical option desirable for smaller-scale testing. Combustion drivers have been shown to be capable of producing very high shock speeds at low cost [3]. They have been in use in facilities of various sizes since the mid-1950s, [1] and their performance has been studied fairly extensively in the literature. A small combustion-driven shock tube (CDST) has been constructed and tested at Caltech to be used as an economical alternative to facilities with higher operating cost in small-scale experiments. A model was developed using Cantera and the Shock and Detonation Toolbox (SDT) to predict the performance of the tube.