煤炭开采过程中，煤自燃始终威胁着矿井的安全生产。随着矿井开采深度和强度的增加，在瓦斯存在的情况下，煤自燃所引发的灾害往往更为严重。在矿井火区中，燃烧的瓦斯很容易将煤引燃，热辐射作为瓦斯燃烧传递热量的主要形式，在很大程度上影响瓦斯燃烧引燃煤体的过程。因此，对热辐射引燃煤体特性和临界条件进行研究，有助于探明瓦斯燃烧引燃煤体的途径，在一定程度上降低煤矿井下煤自燃和瓦斯爆炸的危险，从而减少煤矿重特大事故的发生，保障煤矿安全生产。

本文设计并搭建了热辐射下煤样燃烧特性测试实验台，该实验台包含了热流控制系统、数据采集系统及样件处理装置。通过该实验台对三种热流强度下（11.52kW/m²、8.15kW/m²、5.68kW/m²）、两种不同距离（8cm、12cm）、四种不同粒径(30-60目、60-100目、100-120目、120-180目)的东滩气煤煤样进行热辐射特性测试，研究了不同辐射强度、不同辐射距离，不同粒径煤样对热辐射的响应机制，实现了辐射作用下煤体在氧化燃烧不同阶段表观形态的可视化呈现；测试了煤体氧化燃烧过程中特征温度、质量损失速率的变化特性，并对热辐射条件下煤体升温模型进行了验证。初步确定了煤体被辐射引燃的临界时空条件。

研究表明，热流强度、煤样粒径和火源与煤样之间的相对距离都是影响热辐射引燃煤体的重要因素，在热流强度稳定的情况下改变任何一种变量都可能直接影响煤样燃烧特性。本文根据煤样升温特性，将热辐射条件下煤样燃烧过程为空气域升温、煤体蓄热、煤体燃烧三个阶段，将煤样受热辐射过程中蓄热期和燃烧期的交叉点定为是否发生燃烧的着火点。研究发现，随着热流强度的提高，煤样在最高温度的停留时间变短，升温速率加快；同种热辐射条件下随着煤样粒径的减小，煤样升温速率逐渐升高，蓄热期时间变短，煤样表面干裂程度加剧，小粒径煤样对热辐射的吸收能力更强；辐射热源与煤样之间相对距离的减少会导致氧化燃烧更加剧烈，煤样在各个时期的时间明显缩短，失重速率整体升高且在峰值的持续时间变短。在两种相对距离下粒径为0.975mm的煤样在热流强度小于5.68kW/m²时不会发生自燃。根据热辐射特性测试结果，将热辐射条件下煤体燃烧结果划分成了引燃区和非引燃区，初步确定了热辐射引燃煤体的临界条件，本研究对瓦斯与煤自燃耦合致灾防控具有重要的理论和实际意义。

In the process of coal mining, coal spontaneous combustion has always threatened the safety of mine production. As the mining depth and intensity of mines increase, the disasters caused by spontaneous combustion of coal are often more serious in the presence of gas. In the mine fire area, burning gas can easily ignite coal. Thermal radiation, as the main form of heat transfer in gas combustion, greatly affects the process of gas combustion and igniting coal.Therefore, research on the characteristics and critical conditions of thermal radiation ignited coal is helpful to explore the way of gas combustion ignited coal, to a certain extent, to reduce the risk of coal spontaneous combustion and gas explosion in underground coal mines, and to ensure safe production in coal mines.

This paper designs and builds an experimental platform for testing coal sample combustion characteristics under thermal radiation. The experimental platform includes a heat flow control system, a data acquisition system and a sample processing device.Through the experimental platform, under three heat flow intensities (11.52kW/m², 8.15kW/m², 5.68kW/m²) and two different distances (8cm, 12cm), four different particle sizes (30-60 , 60-100, 100-120, 120-180 mesh) the radiation characteristics of Dongtan gas coal samples. The response mechanism of coal samples with different radiation intensities, different radiation distances and different particle sizes to thermal radiation was studied. Visual representation of the apparent morphology of coal at different stages of oxidative combustion under the action of radiation.The change characteristics of characteristic temperature and mass loss rate in the process of coal oxidation and combustion were tested, and the coal heating model under thermal radiation conditions was verified. The critical time and space conditions for coal ignited by radiation have been preliminarily determined.

Studies have shown that the intensity of heat flow, the particle size of the coal sample and the relative distance between the fire source and the coal sample are all important factors that affect coal by thermal radiation. When the intensity of heat flow is stable, changing any variable may directly affect Combustion characteristics of coal samples.In this paper, based on the heating characteristics of coal samples, the coal sample combustion process under thermal radiation conditions is divided into three stages: air area heating, coal body heat storage, and coal combustion.The study found that as the heat flow intensity increases, the residence time of the coal sample at the highest temperature becomes shorter, and the heating rate increases; under the same thermal radiation condition, as the particle size of the coal sample decreases, the coal sample heating rate gradually increases, and The heat period becomes shorter, the surface of coal samples becomes more dry and cracked, and coal samples with small particle diameters have a stronger ability to absorb thermal radiation; the reduction of the relative distance between the radiant heat source and the coal sample will result in more intense oxidation and combustion. The time for the weight loss is significantly shortened, the overall weight loss rate increases and the duration at the peak becomes shorter.The coal sample with a particle size of 0.975mm at the two relative distances will not ignite spontaneously when the heat flow intensity is less than 5.68kW/m2. According to the test results of thermal radiation characteristics, the coal combustion results under thermal radiation conditions are divided into ignition zone and non-ignitable zone, and the critical conditions for thermal radiation to ignite coal are preliminarily determined. This study has a significant on the coupling of gas and coal spontaneous combustion. This research has important theoretical and practical significance for coal mine disaster prevention.

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