収束するデトネーションの安定性と円筒対称性 膨張デトネーションによる収束デトネーションの発生

Abstract

Oxyacetylene converging detonations are produced using a disk-type vessel of 80cm i.d. which consists of a converging and a diverging sections divided by a diffraction disk. The diverging section is preceded by a pre-run tube.Effects of pre-run tubes on the stability of convergence of detonations are examined. It is found that at initial pressures below 150 Torr, pre-run tubes are necessary in order to obtain stable cylindrical converging detonations.Utilizing a preliminary experimental apparatus with two-dimensional curved channels, the features of diffraction of detonations are observed by means of open.shutter and schlieren photographs. Recovery to the planarity of detonation front after passing through the curved path is found to take relatively long time.The propagation velocity measurement of detonation in the converging section shows that with decreasing radius of the converging wave, it behaves as the cylindrical converging shock wave of the similarity exponent n=0.85.The average pressure measured in the vicinity of the collapsing center of detonation is about 53kg/cmcm2 which nearly equals to 16 times the calculated pressure value of the C-J detonation under identical initial conditions, i.e., the initial pressure 60 Torr and the equimolar oxyacetylene gas mixture. This is close to the value 18 measured by LEE et al. at the initial pressure 190 Torr, using the same mixture.