Electric Arc-Driven Shock Tube

Abstract

A shock tube has been developed capable of producing a gas sample of known conditions by shocks with velocities as high as 43 000 ft/sec. The driver of this shock tube employs a capacitor bank which discharges electrical energy into helium, heating the helium to temperatures of 10 000–20 000 °K, and raising the pressure to 10 000–20 000 psi. The high‐pressure bursts the scribed diaphragm and the resulting shock wave propagates into the test gas. Diagnostic techniques have been employed to investigate the resulting hot gas sample. The growth of this sample has been observed optically and correlations have been achieved with theoretical calculations. The observed radiation has been compared with and can be used to extend the known radiative properties of high temperature air. Time‐resolved luminous pictures and spectra have also been taken to show the purity of the test gas. The speed and attenuation of the shock front have been measured. The observed operation of this shock tube has been compared with theoretical predictions, and although no precise correlation can be made, the driver gas energy transfer and losses in the shock tube boundary layer can be accounted for.