Burning velocities and explosion pressures of acetylene-freon 12-air mixtures in spherical bombs

Abstract

Ternary mixtures of acetylene, air, and dichlorodifluoromethane were exploded in two spherical vessels, one of glass and the other of cast iron, by passing a spark across a centrally located spark gap. Simultaneous records of flame growth and pressure rise were obtained for each explosion in the glass bomb, whereas only pressure-time records were obtained for explosions in the cast-iron bomb. These records were used to determine the burning velocities and maximum explosion pressures in the mixtures. A new equation has been proposed for the determination of burning velocity. This equation was obtained by making certain modifications in the burning velocity equation proposed by Rallis and Tremeer [8] . It is shown that the proposed equation yields reliable values of Su. Experimental data show that, with increasing amounts of Freon 12, the maximum burning velocity and explosion pressure are reduced. However, the burning velocities of rich acetylene-air mixtures having amounts of combustible greater than that at which maximum burning velocity is attained in these mixtures are affected less by the addition of Freon 12 than the burning velocities of lean acetylene-air mixtures. The following correlation has been obtained between the maximum explosion pressure and the burning velocity at the given intitial conditions: P e = A S u m where A and m (