Accession Number : ADA302061

Title :   Characteristics of Alumina Particles from Solid Rocket Motor Exhaust in the Stratosphere.

Corporate Author : AEROSPACE CORP EL SEGUNDO CA TECHNOLOGY OPERATIONS

Personal Author(s) : Beiting, E. J.

PDF Url : ADA302061

Report Date : 15 SEP 1995

Pagination or Media Count : 42

Abstract : Based on currently available data, a unified model for the particle size distribution, particle density, and geometrical dispersion for the alumina particles in the exhaust of a Titan SRM plume in the stratosphere is presented. The particle size distribution is found to be trimodal with Sauter mean diameters of 0.056, 1.0, and 3.6 um for the small, medium, and large size modes, respectively. Nearly all the particles lie within the small size mode, but nearly all the mass lies in the large size mode. About two-thirds of the particle surface area available for heterogeneous chemical reactions is due to the large particle mode while most of the remaining surface area is due to the small particle mode. The light scattering characteristics of the plume were also explored. Mie scattering calculations were used to predict the local attenuation of the plume as a function of wavelength and the total attenuation of a beam of radiation through the plume making an arbitrary angle with respect to the axis of the plume and as a function of time after SRM passage for several wavelengths in ultraviolet, visible, and infrared spectral regions. These studies show that most of the attenuation is due to the large-size mode. An expression for the volume density of total area of the particles is derived in terms of known parameters and the Sauter mean diameter. Mie theory is then used to show that this Sauter mean diameter can be measured using a two-color transmissometer.

Descriptors :   *SOLID PROPELLANT ROCKET ENGINES, *ROCKET EXHAUST, DATA BASES, SPATIAL DISTRIBUTION, DENSITY, LIGHT SCATTERING, PARTICLE SIZE, OPTICAL DETECTION, ENVIRONMENTAL IMPACT, MIE SCATTERING, ALUMINUM OXIDES, TROPOSPHERE, EXHAUST PLUMES, OZONE LAYER, ATMOSPHERE MODELS, LAUNCH VEHICLES, DISPERSIONS, STRATOSPHERE, TRANSMISSOMETERS.

Subject Categories : Combustion and Ignition
      Solid Propellant Rocket Engines
      Atmospheric Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE