颗粒粉尘在通风管道内的运移规律研究

发布时间：2018-01-11 01:15

本文关键词：颗粒粉尘在通风管道内的运移规律研究　出处：《江西理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：众所周知,工业粉尘治理需通过选择合理的除尘方法才能达到较好的降尘效果。目前,带有长管道的机械通风除尘措施是工业粉尘治理的有效措施之一。随着颗粒粉尘在管道内长时间排出,管道内势必会产生沉积现象。如果对其中的颗粒粉尘不采取处理措施,会导致很多不良的后果,特别是在管道内部,轻则粉尘堆积,重则导致管道堵塞、腐蚀等。在进行粉尘清除前,如能对管道内部粉尘运移、沉降的规律有所了解,这对粉尘清除工作以及根据规律重新设计管道结构参数将会起到一定的帮助。本文以工业除尘管道为研究对象,基于流体力学、射流理论和计算流体动力学等理论,通过Fluent6.3.26模拟软件对圆管和方管建立了物理和数学模型,采用Standard k-e模型和标准壁面函数对管道内的风流流场进行数值分析,并模拟了风速、粉尘粒径以及管型对管道内粉尘浓度分布、沉积的影响。主要研究成果如下:(1)选取标准双方程模型可以有效的数值模拟两种管道内部风流流场及不同粒径粉尘的分布。(2)管道壁面压力大小分布受管型以及粉尘粒径影响较小,受风速影响较大。(3)在管道长度达到一定长度后,管道内流速大小分布不受管道长度的影响,当圆管长度大于25m、方管大于30m时,管道内流速分布稳定,变化小。输运风速越大,管道内达到最大速度时的增值△v越大,但达到最大流速位置基本不变,圆管为15m处,方管为18m处。(4)不同粒径粉尘在管道内输运都具有相应的最低沉积浓度输运风速,输运风速太低,达不到粉尘输运的效果;输运风速太高,能耗增大,粉尘与管壁碰撞概率增大;因此在进行通风风速设计时,应当针对不同粒径粉尘选择最佳输运风速。(5)16m/s送风风速下,对于粒径粉尘为0.25μm至2.5μm时,方管内壁上的平均粉尘沉积浓度值要比圆管低。粒径为0.25μm时,方管壁面平均粉尘浓度值比圆管低0.05g/m3;粒径为2.5μm时,方管壁面平均粉尘浓度值比圆管低0.15g/m3;因此针对工业管道在16m/s风速下输运粒径为0.25μm至2.5μm粉尘时,可考虑采用方形管道输运。
[Abstract]:As we all know, industrial dust control needs to select a reasonable dust removal method in order to achieve a better dust control effect. Mechanical ventilation and dust removal with long ducts is one of the effective measures for the treatment of industrial dust. If the particle dust is not treated, it will lead to a lot of adverse consequences, especially in the pipeline, light dust accumulation, heavy lead to pipeline blockage. Corrosion and so on. Before dust removal, such as the pipeline internal dust migration, settlement of the law of some understanding. This will play a certain role in dust removal and re-design of pipeline structural parameters according to the rules. This paper takes the industrial dust removal pipeline as the research object, based on hydrodynamics. Based on the theory of jet and computational fluid dynamics, the physical and mathematical models of circular and square tubes are established by Fluent6.3.26 simulation software. The Standard k-e model and the standard wall function are used to numerically analyze the air flow field in the pipeline, and the distribution of the wind speed, dust particle size and the dust concentration in the pipe is simulated. The main research results are as follows: 1) the standard two-equation model can be used to numerically simulate the airflow field and the distribution of dust with different particle sizes in two pipelines. The pressure distribution of pipe wall is less affected by pipe type and dust particle size. When the length of pipe reaches a certain length, the distribution of velocity is not affected by the length of pipe. When the length of round pipe is more than 25m, the length of square pipe is more than 30m. The velocity distribution in the pipeline is stable and the change is small. The larger the transport wind speed is, the greater the increment v is when the maximum velocity is reached in the pipeline, but the position of reaching the maximum velocity is basically unchanged, and the position of the circular pipe is 15m. The dust transport with different particle size in the pipeline has the corresponding lowest sediment concentration transport wind speed, which is too low to achieve the effect of dust transport. If the transport speed is too high, the energy consumption will increase, and the collision probability between dust and pipe wall will increase. Therefore, in the design of ventilation wind speed, we should select the best transport speed of 16 m / s for different particle size dust, when the particle size dust is 0.25 渭 m to 2.5 渭 m. The average dust concentration on the inner wall of the square tube is lower than that on the circular tube, and when the diameter is 0.25 渭 m, the average dust concentration on the wall of the square tube is 0.05g / m 3 lower than that on the round tube. When the particle size is 2.5 渭 m, the average dust concentration on the wall of the square tube is 0.15g / m ~ (-3) lower than that of the round tube. Therefore, when industrial pipelines transport dust particles from 0.25 渭 m to 2.5 渭 m at 16 m / s wind speed, square pipeline transport can be considered.
【学位授予单位】：江西理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X701.2

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