Accession Number : ADA322767

Title :   Development of a Technique to Determine the Morphology and Dynamics of Agglomerates in Chemically Reacting Flows.

Descriptive Note : Final rept.,

Corporate Author : LOUISIANA STATE UNIV BATON ROUGE DEPT OF MECHANICAL ENGINEERING

Personal Author(s) : Charalampopoulos, Tryfon

PDF Url : ADA322767

Report Date : 13 JAN 1997

Pagination or Media Count : 139

Abstract : An exact formulation was developed for the prediction of the internal electric field of an assembly of Rayleigh particles exposed to an incident radiation field which: (1) satisfies the energy conservation; (2) accounts for self contribution and multiple scattering effects; (3) is invariant to coordinate transformation and (4) is particularly useful for soot diagnostics. Based on this formulation a computer code (AGGL) was written for the computation of extinction, total scattering efficiency factors, and differential scattering intensities for agglomerates. The computations were free of error and resulted in tenfold reduction in computational time. Agglomerates with straight chain configuration were generated in a diffusion carbon/monoxide/air flame seeded with iron pentacarbonyl vapor. Both the primary particle size and the aspect ratio were found to be strong functions of the vapor concentration and aggregate residence time. X-ray diffraction measurements revealed that the particles consisted predominantly of iron oxide(Fe2O3). In situ measurements of the particle dynamics using polarized and depolarized light scattering showed that the signal to noise ratio was significantly improved when measurements were carried out in the cross correlation mode. It was also found that monitoring of the particle dynamics was possible with sampling times as low as 25 nanoseconds.

Descriptors :   *LIGHT SCATTERING, *SOOT, *AGGLOMERATES, EXTINCTION, PARTICLE SIZE, POLARIZATION, COMPUTATIONS, MORPHOLOGY, SCATTERING CROSS SECTIONS, SIGNAL TO NOISE RATIO, X RAY DIFFRACTION, ELECTRIC FIELDS, TRANSFORMATIONS(MATHEMATICS), CONFIGURATIONS, CHEMICAL REACTIONS, DIAGNOSIS(GENERAL), DIFFUSION, INVARIANCE, ENERGY CONSERVATION, ASPECT RATIO, CROSS CORRELATION, IRON OXIDES, DIFFERENTIAL CROSS SECTIONS.

Subject Categories : Organic Chemistry
      Optical Detection and Detectors
      Atomic and Molecular Physics and Spectroscopy
      Combustion and Ignition

Distribution Statement : APPROVED FOR PUBLIC RELEASE