E. W. Price

Bio: E. W. Price is an academic researcher. The author has contributed to research in topics: Propellant & Combustion. The author has an hindex of 2, co-authored 3 publications receiving 129 citations.

The effects of bimodal aluminum with ultrafine aluminum on the burning rates of solid propellants

Abstract: Burning rates were measured for aluminized composite propellants with different aluminum (Al) sizes(monomodal distribution) and with bimodal Al distributions containing various amounts of ultrafine Al (UFAl). Enhanced rates were found for fine Al, with the enhancement increases for reduced Al size. The fine Al also burned in an intense region very close to the propellant surface, suggesting improved heat feedback in the form of radiation and conduction. Major modification of the burning rate could be achieved with moderate amounts of UFAl. Results obtained with various fine oxidizer particle sizes and mass fractions suggest that the degree of burning-rate modification depends on the ability to ignite the UFAl, for example, with leading-edge flames, as well as the availability of oxidizer near the Al-containing regions of the propellant.

Aiaa 2001-0339 intermittent burning and its contribution to plateau burning of composite propellants

Abstract: The plateau burning behavior of composite solid propellants consisting of ammonium perchlorate (AP) and hydrocarbon (HC) binder with a bimodal AP particle size distribution (coarse and fine) is examined. The focus is the weak pressure dependence of the propellant burn rate (i.e., a plateau) in an intermediate range of about 2.7-6.9 MPa (-400-1000 psi). The relationship between the appearance of this mid-pressure plateau for a composite propellant and self-extinction during the burning of the corresponding fine AP/binder matrix (i.e., the propellant formulation without the coarse AP particles) is experimentally examined through the study of a compositional array of propellants, sandwiches (two-dimensional propellants) and matrixes. The burning history of the samples was captured with a highspeed digital camera, and surfaces from quenched samples (burning that was self-extinguished or intentionally interrupted) are analyzed using a scanning electron microscope. The combined results indicate the prevalence of intermittent burning of the matrixes as the pressure is varied across the boundary between continuous burning and self-extinction (burn/no-burn boundary). The burning surfaces are marked by extreme threedimensionality coupled with a redistribution of the fine AP particles and the binder. The results point to the need for a more realistic approach to the underlying processes that contribute to plateau burning rate trends in bimodal composite propellants than has been adopted hitherto.

Combustion Mechanisms of Heterogeneous Solid Propellants

Abstract: : The bulk of the research on this contract was concerned with the mechanisms that cause plateau burning of ammonium perchlorate/hydrocarbon (AP/HC) propellants. The long range goal is to identify the steps in the combustion process that dominate overall burning, and in particular to understand which of these steps in the combustion process lead to plateau burning. Burning alone, matrixes (mixture of binder, fine AP, and catalysts) almost always burn slower than the bimodal propellant at all pressures. The improved burning with a catalyst is probably due to both increased surface layer heat release and to catalytic break down of the large fuel vapor molecules which cause the flame to stand closer to the surface. Deflagration rate of the large AP particles is always lower than the propellant rate, and contributes little to overall rate, except in close proximity to the matrix where a hot stoichiometric diffusion flame occurs and (apparently) supports the marginal matrix burning, accounting for the higher propellant rate. Observations of local intermittency of burning seem to contribute to the low burning rate associated with plateaus and spontaneous quenches.

Combustion of Nano Aluminum Particles (Review)

Abstract: Nano aluminum particles have received considerable attention in the combustion community; their physicochemical properties are quite favorable as compared with those of their micron-sized counterparts. The present work provides a comprehensive review of recent advances in the field of combustion of nano aluminum particles. The effect of the Knudsen number on heat and mass transfer properties of particles is first examined. Deficiencies of the currently available continuum models for combustion of nano aluminum particles are highlighted. Key physicochemical processes of particle combustion are identified and their respective time scales are compared to determine the combustion mechanisms for different particle sizes and pressures. Experimental data from several sources are gathered to elucidate the effect of the particle size on the flame temperature of aluminum particles. The flame structure and the combustion modes of aluminum particles are examined for wide ranges of pressures, particle sizes, and oxidizers. Key mechanisms that dictate the combustion behaviors are discussed. Measured burning times of nano aluminum particles are surveyed. The effects of the pressure, temperature, particle size, and type and concentration of the oxidizer on the burning time are discussed. A new correlation for the burning time of nano aluminum particles is established. Major outstanding issues to be addressed in the future work are identified.