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Laboratory experiments with liquid fuel and ClF3 (CTF) or BrF3 (BTF) have suggested that an effective FAE blast may be obtained by very rapid fuel/ agent dispersion and agent-induced combustion. In the current work, initial small-scale field tests using small pellets of high-explosive for fuel and agent dispersion have yielded significant FAE blasts when performed in open air, no blast when performed in an atmosphere of nitrogen, and a very strong blast when performed in an atmosphere of oxygen. The results show that an agent such as CTF meets the requirements of inducing very rapid combustion, and that the strength of the FAE blast is thus principally governed by the size and configuration of the central dispersing charge. Further small-scale tests are scheduled in which the central charge is substantially enlarged and shaped for injecting high velocity jets of fuel/agent dispersion into the surrounding atmosphere.

It is believed that the second-event system in FAE devices can be eliminated by development of a process in which very rapid fuel dispersion and simultaneous combustion are initiated by a single event. According to this concept, a central explosive charge would drive a highly reactive chemical agent such as chlorine trifluoride (CTF) into a surround of hydrocarbon fuel, with the effect that the fuel would be explosively dispersed and burned in the ambient air, and a FAE blast generated. Laboratory research is described in which small slugs of CTF and BTF (bromine trifluoride) were driven pneumatically into Diesel oil. The ensuing event was diagnosed by high speed motion pictures and blast gages. An FAE effect was reproducibly observed with BTF. With CTF it was found that the agent-fuel reaction is so rapid that a counterforce develops at the interface of the liquids and prevents thorough mixing and reaction. In larger-scale field tests that are planned, CTF will be explosively driven into Diesel oil, thus eliminating this hindrance. It is considered that proof of concept has been demonstrated in the sense that a blast wave has been produced by chemical initiation of a fuel-air-mixture. The concept depends on rapid fuel dispersal accompanied by combustion. These aspects of the concept are scale-dependent.

A new phase of the program, the study of solid propellant and oxidizer extinguishment by rapid depressurization, began during this quarter. In this report we describe the apparatus used for this work and the results obtained on the first propellant tested. The apparatus is an optical strand burner modified to allow rapid depressurization by venting. At pressures of 2000 psi, pressure decay rates of 5 x 10 to the 5th power psi/sec can be achieved. Experiments were carried out on a poly-vinylchloride-ammonium perchlorate composite propellant, over a range of initial pressures of 68 to 430 psia with decay rates as high as 10 to the 5th power psi/sec. The experimental extinguishment results are compared with theory.

Work was initiated on the study of the self-deflagration of hydroxylammonium perchlorate (HAP), and the investigation of solid-oxidizer and propellent extinguishment. The effort to present has principally been devoted to design and construction of apparatus, preliminary calculations and acquiring and analyzing HAP. Progress along these lines is outlined., See also AD642420.

The results of research on the deflagration of the solid-propellant oxidizers, hydrazine perchlorate (HP) and hydrazine diperchlorate (HDP), are reported and discussed. Each compound was found to be unique physically and chemically, in both its low-temperature thermal decomposition and its high- temperature deflagration behavior. HP and HDP are white solids of crystal densities 1.939 and 2.21 g/cc, and melting points of 141 and 191C, respectively. The following aspects of the combustion process were studied: The deflagration rate as a function of pressure and the effects of catalysts; the flame temperature and the temperature profile through the combustion wave; quenching, thermal decomposition, and chemical behavior. In addition, vaporization rates of HP were measured.

Measurements of the flame temperature of deflagrating hydrazine diperchlorate using fine Chromel-Alumel thermocouples have been completed at 28 atm. A value of 1385 + or -35 deg K (corrected for radiation heat loss of the thermocouple) was obtained. Experiments at 55 atm have tentatively put the flame temperature at above 1500 deg K at this pressure. Both temperatures are below the theoretical value of 1600 deg K and indicate that thermodynamic equilibrium is not attained in the flame, although it may be at higher pressures. The temperature profile through the combustion wave was obtained for deflagration at 28 atm. No indication of heat release up to 190 deg C (the melting point of HDP) in the condensed heated zone of the oxidizer was observed. The thickness of the preheat zone was measured as 550 + or -80 microns, and the thermal diffusivity was determined to be 0.0015 + or -.0005 sq cm/sec, for HDP of 2.1 g/cc density.

The chemistry and kinetics of reactions involving various oxides of chlorine were studied using the data obtained in the present investigation in conjunction with data reported in the literature. Additional experiments on the interaction of Cl2O3 with ClO2 were performed in order to obtain more complete information on the effect of kinetic variables. The decomposition of ClO2 is represented by the following reaction mechanism: 2ClO2 (on wall) to ClO + ClO3; ClO2 + Clo to Cl2O3; Cl2O3 + ClO to ClO2 + 2Cl + O2; Cl + ClO2 to 2ClO; Cl + ClO2 to Cl2 + O2; Cl (on wall) to 1/2 Cl2. It is shown that the observed characteristics of the explosive decomposition of ClO2 are fully consistent with the reaction-kinetic equations developed on the basis of this scheme. (Author), See also AD-637 562.