向下火焰延燒寬度與邊牆效應之研究
| Autor: | Wel-Liang Liu, 劉韋良 |
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| Rok vydání: | 2016 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 104 A fire may spread once combustible materials are nearby, and the heat flux onto them is sufficient. The flame spread can be divided into concurrent and counter-current spread, depending on the directions of flame spread and hot gas flow. One of the example of the concurrent flame spread is upward flame spread, while downward flame spread belongs to the counter-current one. The width and sidewall effects with upward flame spread have been studied. This study investigated the existence of width and sidewall effects of downward flame spread experimentally. The material used was 10 mm thick and 1000 mm high PMMA slabs with width of 100, 200, 300, 500 and 700 mm. The presence of sidewalls was studied. Flame height, flame temperature, flame thickness, heat release rate per unit area and flame spread rate were measured. The experimental results show that the width of fuel changes the direction of entrained air flow. The presence of sidewalls helps volatiles flow along the sidewalls, increasing flame thickness. This phenomenon was significant for narrow specimens. The absence of sidewalls resulted in lateral entrained air flow toward the center line of burning fuel. The experimental results show that the width of fuel did not influence the downward flame spread rate with or without sidewalls. Additionally, the downward flame spread rates without sidewalls were higher than those with sidewalls. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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