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Experimental Research And Analysis On Simulation Of Logs Heap Combustion Based On Water Mist

Posted on:2014-04-23Degree:MasterType:Thesis
Country:ChinaCandidate:C WangFull Text:PDF
GTID:2253330401485561Subject:Forest Engineering
Abstract/Summary:PDF Full Text Request
The timber yard is the important place of logging, making woods and transferring woods. Logs stack in the form of log piles in timber yard,so the log pile occupies a vital position in the timer yard.Loggers take harvesting logs in the main of winter in Northeast Forest region,the responsibility of timber yard is storaging logs in the rest of the seasons,which storage an abundance of timbers in spring,spring and autumn are the high incidence of fire that is because of windy and rainless and arid climate in the two seasons,once the fire will cause great loss,so the timber fire research and analysis is especially important. The paper adopts theoretical analysis, experimental research and simulation,which methods to analyze the log pile fire combustion under the action of the water mist.In the aspect of theoretical analysis,this paper introduces the apply to wood burning fire research content,including:classification,the combustion process,combustion temperature,solid calorific value theory of empirical formula,the oxygen consumption principle of heat release rate,and the corresponding mechanism of water mist fire extinguishing and quasi steady state model of water mist fireextinguishing.In experimental studies, this paper conduct burning experiments of log shocked heap in the water mist role in the confined space, and drift experiments of water mist impacting under wind as well. In the burning experiments of stack of logs flute under the action of water mist, measured at different water mist flux; at different time under water mist, determined combustion characteristic parameters such as burning temperature, heat release rate of logs shocked heap; and a corresponding change in the concentration of oxygen, the concentration of carbon monoxide and the concentration of carbon dioxide in the flue gas composition. The drift experiments of water mist impacting under wind was conducted in the environment without natural wind impact. The experiments changed the nozzle spray angle, the nozzle height, and the amount of spray of the water mist in turn; then collect the mist net content within the water mist scoping under the influence of different wind levels. The experiments clarify the relationship between the nozzle spray angle, the nozzle height, the amount of spray and different wind levels, then determined the critical wind scale of experimental collection net amount of water failure.In the simulation, this paper used ANSYS software to simulate a shocked heap’s cooling conditions in the mist. The simulated results were coincided with the experimental results substantially. And through accessing points from the module of shocked heap under different conditions, draw the cooling curve of the different levels of them. Thus it will become the basis for the analysis of the effect of the water mist putting out the shocked heap fire.
Keywords/Search Tags:timber yard, log pile, heat release rate, water mist
PDF Full Text Request
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