Detonation process of high-speed flowing multiphase energetic mixture under high temperature and high pressure

Abstract

The detonation process of high-speed flowing multiphase energetic cloud in a high-temperature and high-pressure semi-confined environment has extensive engineering backgrounds, and is a common form of energy output. A two-dimensional combustor model is established to numerically study the process and propagation laws of hexogen/air explosion, isopropyl nitrate/air explosion and hexogen/isopropyl nitrate/air explosion under 600 m/s flow. The results show that the high-speed flowing multiphase cloud will be subject to a first and second explosion under high temperature and high pressure. Under different concentrations of hexogen/air, the first explosion pressure of mixture is about 1.32 MPa; the second explosion pressure is 1.68–3.11 MPa and the peak temperature is 2732–4084 K, which first increase and then flatten with the increase of hexogen concentration. Under different concentrations of isopropyl nitrate/air, the first explosion pressure is about 1.28 MPa; the second explosion pressure is 1.59–6.49 MPa and two peak temperatures appear obviously during the explosion process, which increase with the increasing isopropyl nitrate concentration. For the three-phase mixture under hexogen: isopropyl nitrate=1:1, the detonation pressure and temperature increase with the increase of mixture concentration. Compared with hexogen/air, hexogen/isopropyl nitrate/air mixture has better detonation performance at high concentration (>1800 g/m3). The detonation performance of hexogen/isopropyl nitrate/air mixture at hexogen ratio ≤30% is similar to that of pure hexogen/air, and at proportion ≥40% is close to that of pure isopropyl nitrate/air. As the hexogen ratio increases, the explosion pressure and temperature of three-phase cloud present an inverted 'V' shape and reach the maximum when the hexogen ratio accounts for 90% of the multiphase mixture, which indicates that the detonation process of the three-phase hexogen/isopropyl nitrate/air mixture is the mutual coupling of decomposition exothermic reaction of hexogen and oxidation reaction of isopropyl nitrate and oxygen.