Experimental study of the interaction between aluminum and hydrogen fluoride in biocidal explosions

The research presented in this thesis was performed in order to develop a technique for quantitatively measuring the temperature and concentration of hydrogen fluoride (HF) in complex, turbulent flows. These diagnostics were used to investigate the potential suppression of the biocidal species due to aluminum interaction in situ. In the field of counter chemical and biological warfare, explosives are used to evolve spore-killing, and neutralizing agents. Current efforts involve collaboration between experimental and computational laboratories to develop thermochemical models for the biocidal environment. Experiments were conducted to make time resolved, optical measurements that assess the degree of chemical non-equilibrium in these events. From the data collected, the amount of HF generated and rate of equilibration in the biocidal environment was able to be determined. Two different types of experiments were conducted. The initial set of experiments was designed to closely replicate the detonation of a counter weapon of mass destruction (C-WMD) armament. These tests involved the use of high explosives coupled to solid state halogen fuels. The second thrust area was to create an explosion that replicated the kinetics of the post C-WMD detonation, but simplified the environment to allow higher quality measurements. The simplified explosions used gas phase halogen fuel (1,1-difluoroethane) diffused into a propane/air explosion with pneumatically injected powdered particulates. The results showed that neither the presence of aluminum, nor alumina, suppressed the HF population in the first second of the explosion. The data suggested that if the injected aluminum ignites, it preserves higher concentrations at lower temperatures

Diode laser gas sensing for high-speed temperature and speciation measurements inside explosive fireballs

There is a need for fundamental science to defeat weapons of mass destruction. Prompt bioagent defeat strategies invoke energetic materials to generate spore killing temperatures and halogen compounds. Developing predictive models for the bioneutralization efficiency of materials requires accurate experimental data to underpin the computational efforts. Certain thermodynamic parameters such as pressure are easily obtained in explosively driven flows. The temperature and chemistry of the interior of post-detonation fireballs is largely unmeasured at the current time. The present work was carried out in order to develop, demonstrate, and transfer technologies for making cost effective, high-speed, quantitative measurements of temperature and chemical speciation in near-field, post-detonation fireballs. This document presents the details of a hardened gauge that enables the fielding of a wide variety of proven tunable diode laser absorption techniques in explosive applications. In addition, details of the theory, application, and data analytics for the relevant spectroscopic measurements are also addressed. The developed hardware and technique were used to measure temperature at 30 kHz in chambered explosive fireballs by sweeping a tunable diode laser over a water vapor absorption band in the near infrared spectrum. Additional efforts were made to characterize the multiphase temperature of explosive fireballs. In addition to measuring temperature, a second tunable diode laser diagnostic was interfaced with the probe to measure atomic iodine in explosive fireballs as it is a halogen useful in agent defeat applications. Test data presented in this document were collected at a variety of scales ranging from milligrams of spark ignited thermites in a 2-liter chamber, to 10s of grams of aluminized, plastic explosives in an 1800-liter chamber. All data validate the ability of the combined probe and data analytics to survive the implicitly destructive intensity of explosive detonation and make high-speed optical measurements of temperature and atomic iodine concentration inside explosive fireballs

Diode laser gas sensing for high-speed temperature and speciation measurements inside explosive fireballs

There is a need for fundamental science to defeat weapons of mass destruction. Prompt bioagent defeat strategies invoke energetic materials to generate spore killing temperatures and halogen compounds. Developing predictive models for the bioneutralization efficiency of materials requires accurate experimental data to underpin the computational efforts. Certain thermodynamic parameters such as pressure are easily obtained in explosively driven flows. The temperature and chemistry of the interior of post-detonation fireballs is largely unmeasured at the current time. The present work was carried out in order to develop, demonstrate, and transfer technologies for making cost effective, high-speed, quantitative measurements of temperature and chemical speciation in near-field, post-detonation fireballs. This document presents the details of a hardened gauge that enables the fielding of a wide variety of proven tunable diode laser absorption techniques in explosive applications. In addition, details of the theory, application, and data analytics for the relevant spectroscopic measurements are also addressed. The developed hardware and technique were used to measure temperature at 30 kHz in chambered explosive fireballs by sweeping a tunable diode laser over a water vapor absorption band in the near infrared spectrum. Additional efforts were made to characterize the multiphase temperature of explosive fireballs. In addition to measuring temperature, a second tunable diode laser diagnostic was interfaced with the probe to measure atomic iodine in explosive fireballs as it is a halogen useful in agent defeat applications. Test data presented in this document were collected at a variety of scales ranging from milligrams of spark ignited thermites in a 2-liter chamber, to 10s of grams of aluminized, plastic explosives in an 1800-liter chamber. All data validate the ability of the combined probe and data analytics to survive the implicitly destructive intensity of explosive detonation and make high-speed optical measurements of temperature and atomic iodine concentration inside explosive fireballs.LimitedAuthor requested closed access (OA after 2yrs) in Vireo ETD syste