Sintering of model aerosol agglomerates
- California Institute of Technology, Pasadena, CA (United States)
Many processes form particles from vapor phase precursors, whereby particles nucleate and grow primarily by coagulation in the solid state. In some industries, such as those that produce fumed titania, silica, and carbon black, these particles are the desired end product. In other processes particle formation can be deleterious, such as the ashes produced by combustion processes which can foul heat transfer surfaces and be environmentally hazardous. Regardless of process, it is important to be able to understand and predict the structure of the particles being produced. The evolving particle population often only partially coalesces (or sinters) during coagulation, leading to agglomerate structures. Although the extent sintering during agglomeration has been described in a number of modeling studies and demonstrated qualitatively in several experimental investigations, no direct validation of those models has been reported. We report on controlled experimental investigations of the structural evolution of model agglomerate particles aimed at providing the necessary data base for such validation as well as a new modeling ideas designed to give a better physical understanding of the sintering process. Aggregate particle densification studies have been performed using mobility classified particles produced by low temperature, non-coalescent coagulation. Initial experiments were performed with small aggregates, primarily bispheres. The particles were thermally processed while still entrained in a carrier gas flow, and subsequently collected for electron microscope analysis of neck growth and other structural parameters. Larger aggregate particles, also produced by low temperature coagulation, have been similarly processed. Changes in the physical structure and aerodynamic drag of the particles have been examined. We have developed a model to describe the structural evolution of simple aggregates during sintering.
- OSTI ID:
- 166537
- Report Number(s):
- CONF-9510126-; TRN: 95:008181-0028
- Resource Relation:
- Conference: Annual meeting of the American Association for Aerosol Research, Pittsburgh, PA (United States), 9-13 Oct 1995; Other Information: PBD: 1995; Related Information: Is Part Of American Association for Aerosol Research (AAAR) `95; PB: 464 p.
- Country of Publication:
- United States
- Language:
- English
Similar Records
Combustion fume structure and dynamics. Semiannual report, February 16, 1994--August 15, 1994
Combustion fume structure and dynamics. Semiannual report, August 16, 1993--February 15, 1994