In the present work, the quenching of gaseous hydrocarbon-air flames in packed beds of spherical particles has been investigated experimentally. Experiments were carried out in the standard flammability apparatus of Coward and Jones modified by the insertion of a packed bed of solid monosize spheres in the flame tube. Laminar flames were spark-initiated in quiescent combustible mixtures and failure or successful transmission of the flames through the packed bed was determined by visual observation. The quenching limits were determined as a function of the packed bed parameters (i.e., sphere material, sphere size, length of packed bed, etc.) to elucidate the mechanisms of flame extinction in the bed of spherical particles. The results have direct application to the design of flame arrestors using a packed bed as the flame arresting element. / The flame quenching limits are found to be relatively insensitive to the material of the solid spheres, but are dependent on the sphere size through a characteristic length scale that describes the open passages of the packed bed. Flame extinction was always observed to occur within a few millimeters of penetration into the packed bed section indicating that the length of the packed bed has little influence on the quenching of laminar flames. Analysis of the experimental results indicates that the mechanism for flame quenching in a packed bed is governed primarily by heat loss to the sphere surfaces by conduction, convection effects being negligible in the small channels of the packed bed. It is shown that, while conduction is the dominant flame quenching mechanism, selective diffusion and flame stretch also play an important role in the quenching process.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.33337 |
| Date | January 2000 |
| Creators | Mihalik, Teresa Ann. |
| Contributors | Lee, John H. S. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Engineering (Department of Mechanical Engineering.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001782260, proquestno: MQ70646, Theses scanned by UMI/ProQuest. |
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