Development of an algorithm for the calculation of the scattering properties of agglomerates

Abstract

A new, improved, and more efficient algorithm for calculation of the scattering, extinction, and absorption characteristics of agglomerates consisting of Rayleigh-size primary particles is presented. The computer code is based on a new formulation of the light scattering for such agglomerates and is more than 10 times faster than the codes based on previous formulations. The computational times required by the old and the new algorithms, run on VAX 7000, IBM 3090, and UNIX RS6000 mainframe computers, are compared for different agglomerate configurations, such as straight chains, clusters, and randomly branched chains. A distributed-parallel-computing scheme was used to run the new algorithm on four UNIX RS6000 processors concurrently, resulting in computational times 47 times faster than required for the calculations. Furthermore, the robustness and convenience of the algorithm are assessed.

The discrete dipole approximation: An overview and recent developments

“…Hull et al [80] applied CM DDA to Diesel soot particles. LC was applied [81] to the computation of light scattering by randomly branched chain aggregates. Lumme and Rahola [40] studied scattering properties of clusters of large spheres (each modeled by a set of dipoles) with the a 1 -term method considering astrophysical applications.…”

Subsídios ao estudo da transferência de calor em uma câmara de combustão cilíndrica horizontal na presença de fuligem

“…Outras técnicas foram desenvolvidas para avaliar as propriedades ópticas das partículas de fuligem, utilizando lâmpadas de xenônio (Vaglieco, Beretta e D'Alessio, 1990), radiosímetros (Babikian, Edwards, Karam, Wood e Samuelsen, 1990), e a combinação entre espalhamento e extinção de luz laser ( Felske e Ku, 1992). Também foram desenvolvidos modelos para ajustar os dados experimentais e considerar efeitos da forma e da aglomeração de fuligem (Ku e Shim, 1991;Charalampopoulos e Hahn, 1991;Charalampopoulos e Chang, 1991;Venizelos, Lou, Tryfon e Charalampopoulos, 1996). Foi observado por Ku e Shim (1991) Lou, Chen, Sun e Zhou (2010) revisaram as principais técnicas de medição aplicadas à fuligem presente em chamas, entre elas a extinção de luz, diagnóstico de partículas por amostragem termoforética seguida de análise por microscopia eletrônica, densitometria por termopar, incandescência induzida por laser, método das duas cores e tomografia calculada por emissão.…”