Experimental Study On Multiphase Detonation Characteristics Of Gas-Liquid-Solid Mixture

The study of multiphase detonation focuses on the initiation, propagation and structure of the detonation. The research of multiphase detonation attracts the attention of numerous scientists for its formidable task and fundamental significance to the detonation field. This thesis studies the detonation characteristics of gas-liquid-solid mixture which is composed of fuel-RDX-air with the help of vertical detonation tube and experimental system. The main work and conclusions are as follows:(1) The critical energy for direct initiation of detonation were measured in vertical detonation tube by Bruceton method with four fuel-air mixtures and four fuel-RDX-air mixtures. The result suggests that the relationship of critical initiation energy and equivalence ratio shows an "U" shape curve, and the corresponding equivalence ratio of the minimum of critical initiation energy is larger than one. The relationship of critical initiation energy is PO <IPN<mixed solvent<petroleum ether. In condition of a certain liquid fuel equivalence ratio, the critical initiation energy for direct initiation of detonation of the fuel-RDX-air system is much lower than that of the fuel-air system. This indicates that fuel-RDX-air system owns a higher chemical reactivity and more likely to reach detonation state than the fuel-air system does.(2) Under the same experimental conditions, the fuel-air two-phase cloud detonation propagation velocity is1500to1600m/s and detonation pressure is2.0-2.5MPa. For fuel-RDX-air three-phase detonation propagation velocity is1700to1800m/s, and detonation pressure is5.5～6.0MPa. This indicates that thermal decomposition of RDX cause by the shock effect and the oxidation of the fuel and oxygen reaction can be mutually coupled to form a reaction zone so as to maintain a higher pressure and the propagation velocity of the wave front. We also studied the RDX concentration on the state of detonation of the fuel-RDX-air. While RDX concentration is low, increase the concentration of RDX, the detonation pressure and detonation velocity increased significantly. However, once the concentration reaches a certain value, the pressure and velocity grow slowly in spite of the increasing RDX concentration.(3) The cell sizes of fuel-RDX-air mixtures were experimentally measured in different conditions using smoke foil technique. In the condition of equivalence ratio level, the cell size of fuel-RDX-air mixture is smaller than that of the fuel-air mixture, which further confirms that RDX involve in the mixture helps to increase the system’s explosion sensitivity. And the ratio of its length to width is smaller than the gaseous fuel’s. Therefore, the fuel-RDX-air detonation mechanism is different from gaseous detonation. With the enhancement of RDX concentration, it will lead to a far more complex cellular structure.