A simple shock tube with detonating driver gas

Abstract

A 2 1/2 in. diameter double-diaphragm shock tube, with cold hydrogen driving into an explosive oxyhydrogen mixture in the middle section, has been used to obtain shocks to Mach 13 in N2or Ar, with a driver pressure of under 10 atm . There are two possible conditions to obtain uniformly driven final shocks, (1) an over-driven primary detonation, and (2) a detonation following reflexion of the shock at the second diaphragm, with shock velocity selected so that the detonated gas is just brought to rest until the second diaphragm breaks. The first condition could not be achieved experimentally because of w ave interactions following delayed diaphragm rupture. The second condition, with the reflected detonation, can be achieved with 3H2+ O2mixtures; calculations, with a computer, have been made for optimum conditions at various driver pressures. For a driver at 9.6 atm a pressure of explosive mixture of 169 mm Hg is required to give a uniform final shock. The shock-heated gases have been studied by spectrum -line reversal observations of temperature, a xenon lamp being used as background. At 5600°K there is delayed dissociation of N2. This type of shock tube is relatively simple and suitable for small-scale laboratory research.