On detonation in gaseous mixtures at high initial pressures and temperatures

I.Detonation in Acetylene and Pentane Mixtures .— Observations on detonation in acetylene and pentane mixtures at ordinary pressures with the object of finding the position of detonation in a tube under set conditions, were described in the previous paper. The present paper extends this work, but at higher initial pressures and temperatures. Apart from the study of detonations in engines, and experiments in explosion bombs where the pressure rise is observed, very little appears to have been done to extend the work of Le Chatelier and of Dixon on rate of propagation of combustion to regions of high pressure. The highest pressure at which explosions were photographed by Le Chatelier and by Dixon were about one and a half to two atmospheres. Woodbury, Canby and Lewis using a bomb of 12 inches length succeeded in photographing explosions in acetylene air mixtures at pressures up to 4 atmospheres. They also investigated the effect of initial temperature (up to 125° C.). The results are referred to by Brown, Leslie and Hunn who find that for any initial density or pressure there should be a certain maximum value of the initial temperature to provide a maximum rate of rise of pressure on exploding a given gaseous mixture; decrease in density of charge on rise of temperature overcomes the effects of increase in reaction velocity.