Тушение тлеющего горения опилок

Abstract

Проанализированы теоретические и известные экспериментальные исследования по тлеющему горению опилок. Разработана методика определения характеристик очагов тлеющего горения. Экспериментально обоснован модельный очаг тлеющего горения. Показано изменение скорости тлеющего горения, массы опилок в зависимости от их дисперсности. Разработана лабораторная методика определения эффективности тушения различными огнетушащими веществами тлеющего горения опилок. Получены экспериментальные результаты по тушению опилок газовыми огнетушащими веществами (ГОТВ), тонкораспыленной водой, а также огнетушащим порошком. The analysis of existing theoretical and experimental studies on smoldering combustion of sawdust is carried out. There are considered the types of smoldering combustion. Practically, there is observed the implementation of three types of smoldering combustion. The first type is the process of oil-carbon sludge smoldering in the final phase of wood burning. The second type is smoldering combustion in dispersed, layered or fibrous carbon-containing materials. The third type of smoldering combustion is typical for carbonaceous materials that do not contain volatile components such as activated carbon. The method for determining the characteristics of seats of smoldering combustion is developed. Wood sawdust of coniferous species of different fractions was used for research. Experimental seats were cylindrical containers with a wall thickness of 1 mm: d = 66 mm, h = 100 mm; d = 72 mm, h = 80 mm; d = 54 mm, h = 100 mm; d = 65 mm, h = 115; d = 100 mm, h = 40 mm; d = 85 mm, h = 85 mm; d = 100 mm, h = 125 mm (d - diameter, h - height of the seat). Smoldering combustion model seat is experimentally proved. Based on the tests performed, a model seat with the height of 85 mm and the diameter of 85 mm was selected for further research (the criterion for seat selecting was the optimal degree of sawdust burnout), in which thermocouples were placed, according to Fig.1. There were used sawdust fractions of less than 0,1 mm, 0,1-0,2 mm, 0,2-0,4 mm and 0,4-1 mm. Sawdust moisture content w = 5 %. Tests were conducted to determine the rate of sawdust smoldering combustion and the maximum temperature of smoldering combustion. There is shown the change both of smoldering combustion rate and the sawdust mass depending on its dispersion. A laboratory method for determining the extinguishing effectiveness of sawdust smoldering combustion with various fire extinguishing agents was developed. The seat was placed into the conventionally sealed chamber of 1 m x 1 m x 1 m at the distance of 0,5 m from the walls. The chamber has lines for supplying bulk fire extinguishing agents, as well as devices for supplying fire extinguishing powders. There are obtained experimental results for extinguishing sawdust with gas fire extinguishing agents, dispersed water as well as with fire extinguishing powder