Simulation And Division Of Danger Areas Of Smoke Flow Of Belt Fire In Coal Mine

Conveyor belt fire is a common exogenous fire of coal mine.There are many combustible materials in the roadway.In case of fire,the conveyor belt fire would develop rapidly.The toxic smoke with high temperature,which is released from the typical tunnel fire,would seriously threaten the life and health of workers employed inside of mine.Therefore,it is necessary to study the smoke flow law of belt fire and the dangerous area of smoke flow.The content of this article is that the dangerous areas of roadway space are divided by analyzing the change rules of temperature field and concentration field of smoke.Through induction and summary,combustion characteristics and causes of belt fire were analyzed.According to the development process of fire in confined space,the development process of the belt fire was divided into the initial stage,the developing stage,the fierce stage,decaying stage and quenching stage.And initial stage and developing stage were the key point of the research.Then,the combustion experiment of belt on flat tunnel fire test platform was done under 5 kinds of wind speed of tunnel inlet.The conclusion was that the mass loss rate of belt combustion was the biggest at 0.4m/s.Under the optimum experimental condition of wind speed to simulate the smoke spread of belt fire in the initial stage,the change rules of the temperature field and concentration of CO and CO₂ with the time and space in the initial stage of belt fire were studied and the characteristics of smoke flow were gotten.At the same time,based on Fluent,a numerical simulation software,taking the experiment as a prototype,the fire model was designed to simulate the smoke flow in developing stage of belt fire.And the change rules of the temperature field and concentration of CO and CO₂ with the time and space in the developing stage of belt fire were studied were obtain.The toxic smoke with high temperature was evaluated.By establishing the smoke evaluation index about high temperature and toxicity,the danger areas of smoke spread were divided in initial stage and developing stage of belt fire.Integrating the division results of toxicity and high temperature,the whole roadway space was safe at the initial stage,while there was sub-safe area near the fire source.At the developing stage,the roadway space was divided into four areas,including safe area,sub-safe area,moderate danger area and danger area.The ranges of the four areas changed with the development of the fire.In addition,compared to the unsafe area of the high temperature,the range of unsafe area of toxicity was greater and the degree of danger was higher.The result of toxicity division showed that the reduction rate of range of safe area was 0.13?0.38m/s and the increase rate of range of danger area was 0.04?0.32m/s.