The measurement of pressures developed in explosion waves

Abstract
The measurement of the pressure produced in the “explosion-wave” in gaseous mixtures is difficult because of the rapidity of movement of the wave and the short time for which the pressure over any given area lasts. In 1894 Dixon and Cain pointed out that the pressures obtained by firing a mixture in a closed vessel did not correspond to pressures in the wave front. Following a suggestion of Mallard and Le Chatelier, they used a method in which glass tubes of known strength were fractured by the explosion-wave, it being assumed that “if a pressure is produced in a glass tube greater than it can stand, the glass will be broken although the pressure may only last for a very short interval of time.” The strength of the glass tubes was found by determining the static pressures required to break similar pieces. It was found that three lengths from the same piece of glass tubing required respectively 890, 950 and 1220 lbs. per square inch to fracture them: the accuracy of the results was therefore not very great. Dixon and Cain estimated that the pressure in the explosion-wave in C2N2 + O2 lay, probably, between 70 and 120 atmospheres and that in C2N2 O + 2N2 between 63 and 84 atmospheres. Jones and Bower cast some doubt on the pressures given by Dixon and Cain, and suggested that they were the pressures produced just after detonation had been re-established when the explosion-wave had been damped down at a junction. The pressure in the wave front of the fully established detonation wave in the mixture C2N2 + O2 was estimated by Jones and Bower to lie between 58 and 75 atmospheres.

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