【作者】 张大明；

【导师】 马云东；

【作者基本信息】 辽宁工程技术大学 ， 采矿工程， 2010， 博士

【摘要】 本文以巷道内皮带输煤系统作为研究对象,采用理论分析、实验研究,现场测试和数值模拟相结合的方法,在不同条件下对巷道内皮带输煤系统煤尘的运移、沉降和二次飞扬的规律,以及皮带输煤系统煤尘治理技术和优化除尘参数进行了基础研究。本文采用稀相气固两相流理论,对输煤巷道内煤尘颗粒与气体耦合运动进行了研究,分别对输煤巷道内煤尘颗粒进行了动力学分析,建立了球状煤尘颗粒沉降运动力学模型,建立了不规则形状煤尘颗粒群悬浮速度力学模型,建立了巷道内煤尘颗粒悬浮运动方程,建立了巷道内悬浮煤尘颗粒群运动方程。并结合阜新五龙矿一区段运输平巷作为沉积煤尘分布实验巷道,对沉积煤尘分布进行了测试和分析,得出沉积煤尘的粒径随运移距离的增加而越来越小,主要是因为大颗粒煤尘能够在自身重力作用下而沉降,湍流扩散作用对其影响较小;而小颗粒煤尘受到湍流扩散影响较大,沉降相对比较困难;且沉积煤尘粒径主要在1~100μm,其中位径为11~24μm。通过理论分析及实验方法对沉积煤尘颗粒在风流中二次飞扬进行了研究,得到冲击力是煤尘二次飞扬的主要动力。同时,得出尘粒的重力及水滴对煤尘颗粒的表面张力是限制尘粒飞扬的主要因素,并对在一定条件下,扬尘风速、尘粒湿度、尘粒粒径三者之间关系进行了研究,从而为皮带输煤系统采取喷雾降尘措施阻止沉积煤尘的飞扬提供理论依据。利用FLUENT流体动力学软件对输煤巷道内煤尘运移、沉降规律进行了数值模拟,建立了尘粒悬浮风速与粒径关系和沉积煤尘二次飞扬扬尘风速与粒径之间的关系,以及巷道内皮带输煤系统转载点处煤尘在不同风速下的扩散规律。同时,通过模拟验证了单个沉积煤尘颗粒飞扬与沉积颗粒群飞扬机理的不同。以上述理论研究作为基础,确定巷道内皮带转载点处采用密闭负压控尘技术为主,皮带输煤系统采用粉尘浓度超限自动喷雾降尘技术为辅的除尘方案,同时对巷道除尘参数进行了优化研究。更多还原

【Abstract】 This thesis takes the coal belt conveyer system in roadway as the research object, by combining different methods such as theoretical analysis, experimental study, field testing and numerical simulation, to carry out the fundamental research on the regulation of transportation, sedimentation and second flying of coal dust in the coal conveyer belt roadway in different conditions,as well as the dust treatment technologies and the parameter optimization of dedusting.This thesis adopts the dilute phase gas-solid two-phase theory to study the coupled motions of the coal dust particles and gas in the coal belt conveyer roadway, respectively carries out the dynamic analysis on the dust particles in the coal belt conveyer roadway, establishes the kinetic model of the spherical dust particle subsiding motion, the mechanical model of the suspension velocity for the irregular shape dust particles, the motion equation of the dust particle suspension in roadway, and the motion equation of the dust particle group suspension in roadway.By taking the transport Lane of Wulong mine of Fuxin as the experimental roadway for sediment coal dust distribution, the sediment coal dust distribution is tested and analyzed, and the conclusion that the particle size of the sediment coal dust becoming smaller with the increasing of the transport distance, which is mainly because the coal dust of large particles can sediment by their own gravity and the turbulent diffusion has little effect on them; while the sedimentation of the small particles are more affected by the turbulent diffusion, so their sedimentation is relatively difficult, and the particle size of the sediment coal dust is mostly from 1 to 100μm, among which the middle size is from 11 to 24μm.Through theoretical analysis and experimental methods to sedimentary coal dust in roadway, the collision force is the main force of the second flying of coal dust. Meanwhile, the dust gravity and the surface tension of the droplet on the dust particles are the main factors that limiting the dust fly-up. The relationship among the wind speed of the dust fly-up, the humidity and dust particle size of the dust particles is studied, thereby providing the theoretical foundation for preventing the flying of the sediment dust by adopting spraying measurement for the coal conveyer belt system. Regularities of dust transportion and sedimentation in the coal conveyer roadways are simulated by fluid dynamics software FLUENT. Through simulation, the relationship between the wind velocity of the suspension particles and the particles size, and the relationship between the second flying wind velocity of the sediment coal dust and the particles size is established, the dust diffusion regularity at the transpersite of the coal belt conveyer system at different wind speed is also built. Meanwhile, the mechanism of the second flying of the single sediment particle and the sediment particle group is proved to be different by simulation.Based on above theoretical studies, the dedusting program of using the airtight negative pressure dust-control technology at the transfer point of coal conveyer belt as the main measurement, and using dedusting technology that the dust concentration limit control automatic spraying in the belt transportation system as the assistant dedusting measurement, while the optimization of dedusting parameters for roadway is also studied.更多还原