【作者】 李哲；

【导师】 葛少成；

【作者基本信息】 太原理工大学 ， 安全工程（专业学位）， 2023， 硕士

【摘要】 煤炭在筛选的过程中,不可避免地造成大量粉尘逸散,不仅危害作业人员的身体健康,更会对安全生产造成不良影响,因此必须对粉尘进行有效防控以规避严重后果。为实现对煤尘的有效防控,专家学者做了大量的实验研究,旨在达到理想的降尘效果,本文在磁化水降尘的基础,提出磁-电耦合喷雾降尘技术,并通过理论分析,数值模拟和实验研究的方法对磁-电耦合喷雾降尘效果进行研究。首先通过理论分析的方法研究水溶液理化性质的变化。普通水溶液经过磁场后物理性质发生改变,以此为基础分析磁化水溶液的捕尘机理,水溶液经过磁化作用后再通过外加电场,液滴荷电,在溶液润湿性增加的基础上更能吸引粉尘,对粉尘进行有效捕捉。研究表明:磁场作用会使溶液的水分子作用力发生改变、大分子团簇断裂成小分子、分子间距增大、径向分布改变、扩散系数增加、溶液内聚能减小,磁化水溶液的雾化性能改变,导致润湿性能也发生改变;增加外加电场,液滴带上电荷后对尘粒的吸引能力增强,也更易破碎,雾化过的液滴更小,密度更大,与煤尘接触机率增大,吸引煤尘的同时更好的浸润粉尘,提高降尘效率。其次通过实验研究的方法分析磁化水润湿及雾化性能。搭建动、静态实验研究平台探究磁化强度、磁化时间和磁化放置时间对磁化水溶液润湿性能和雾化性能的影响。研究结果表明:磁化水性能与磁化强度、磁化时间和磁化放置时间之间并非呈现线性关系,而表现为多极值变化规律,证明存在最佳磁化参数。当磁化强度为350 m T,磁化时间为30 min、磁化放置时间为25 min时,磁化水溶液润湿性能和雾化性能均最佳。再次以最佳磁化水溶液的参数为基础,增加外加电场探寻磁-电耦合作用的荷电及雾化性能。通过搭建的荷质比测量装置和磁-电喷雾雾化粒径测试系统探究电极电压、电极环参数、电极环距离和喷雾压力对磁-电耦合作用的溶液的荷电及雾化性能的影响。研究结果发现其荷电特性与雾化特性变化规律几乎一致,荷电特性越好雾化性能越佳,仅有荷电电压最佳参数有所不同。是由于电极电压过高时液滴出现相互吸引现象,液滴开始凝并,即便此时荷电性能不是最佳,但此时的粒径出现了增大趋势,不利于粉尘的捕集。故磁-电耦合作用的最佳捕尘参数为电极电压9 k V、电极环参数8 cm、电极间距3.5cm和喷雾压力0.4 MPa,此时雾滴对煤尘颗粒的吸引能力增强,粒径分布均匀且足够小,捕尘效率显著提高。最后通过数值模拟和实验研究相结合的方式,从微观和宏观两个角度证实了磁-电耦合作用下的溶液能够有效捕捉粉尘。采用Comsol模拟软件从微观角度创建液滴-球形煤尘碰撞颗粒模型,模拟普通水、磁化水和磁-电耦合液滴与煤尘颗粒碰撞时的形态变化,搭建自动化可视多因素耦合的除尘实验平台从宏观角度对比分析普通水、磁化水和磁-电耦合水溶液的降尘效率。研究结果表明:磁-电耦合作用下的液滴更易黏附在煤尘颗粒表面,铺展范围更大,包覆范围扩大了44.98%;且三种溶液对粉尘包括全尘和呼尘沉降作用的降幅由大到小排序均为:磁-电耦合溶液>磁化水溶液>普通水溶液,全尘时磁-电耦合喷雾捕尘效率相比普通水溶液降尘效率提高38.84个百分点,降尘效率达到91.2%;呼尘时磁-电耦合喷雾捕尘效率相比普通水溶液降尘效率提高38.59个百分点,降尘效率达到82.3%。更多还原

【Abstract】 In the process of coal production and transportation,it is inevitable to cause a large amount of dust to escape,which not only endangers the health of operators,but also has a negative impact on the safety of production.Therefore,effective prevention and control of dust must be carried out to avoid serious consequences.In order to achieve effective prevention and control of coal dust,experts and scholars have done a large number of experimental studies,aiming at achieving ideal dust removal effect.Based on the dust removal of magnetized water,this paper puts forward the dust removal technology of magnetic-electric coupling spray,and studies the dust removal effect of magnetic-electric coupling spray through theoretical analysis,numerical simulation and experimental research.Firstly,the change of physical and chemical properties of ordinary aqueous solution after passing through magnetic field was analyzed by theoretical analysis.On this basis,the dusttrapping mechanism of magnetized aqueous solution was analyzed.After magnetization,aqueous solution could attract dust more effectively and capture dust with the increase of solution wettability by applying applied electric field to charge droplets.The results show that the magnetic field can change the water molecular force,break the large molecular clusters into small molecules,increase the molecular spacing,change the radial distribution,increase the diffusion coefficient,decrease the cohesion energy of solution,change the atomization performance of magnetized aqueous solution,and lead to the change of wettability.When the applied electric field is increased,the droplet with electric charge is more attractive to dust particles and more easily broken.The atomized droplet is smaller and has higher density,and the contact probability with coal dust is increased,which can better infiltrate dust while attracting coal dust and improve dust removal efficiency.Secondly,the wetting and atomization properties of magnetized water were investigated by experimental methods.Dynamic and static experimental research platforms were established to explore the effects of magnetization intensity,magnetization time and magnetization placement time on the wettability and atomization performance of magnetized aqueous solutions.The results show that there is no linear relationship between the properties of magnetized water,the magnetization intensity,the magnetization time and the magnetization placement time,but the multi-extremum variation rule,which proves that there is an optimal magnetization parameter.When the magnetization intensity is 350 m T,the magnetization time is 30 min,and the magnetization placement time is 25 min,the wettability and atomization performance of the magnetized aqueous solution are the best.Thirdly,based on the parameters of the optimal magnetized aqueous solution,the applied electric field is added to explore the charged atomization performance of magnetic-electric coupling.The influences of electrode voltage,electrode ring parameters,electrode ring distance and spray pressure on the charge and atomization performance of the magneto-electric coupling solution were explored through the established charge-mass ratio measuring device and the magneto-electric spray atomizing particle size testing system.The research results show that the variation rules of charging characteristics and atomization characteristics are almost the same.The better the charging characteristics,the better the atomization performance,only the best parameters of charging voltage are different.It is because the droplet attracts each other when the electrode voltage is too high,and the droplet begins to coagulate.Even if the charge performance is not the best at this time,the particle size at this time shows an increasing trend,which is not conducive to dust collection.Therefore,the optimal dust collecting parameters of the magnetic-electric coupling effect are electrode voltage 9 k V,electrode ring parameter 8 cm,electrode spacing 3.5 cm and spray pressure 0.4 MPa.In this case,the adsorption ability of the coal dust particles is enhanced,the particle size distribution is uniform and small enough,and the dust collecting efficiency is significantly improved.Finally,through the combination of numerical simulation and experimental study,it is proved that the magnetic-electric coupling solution can effectively capture dust from both micro and macro perspectives.Comsol simulation software was used to create a droplet-spherical coal dust collision particle model from a microscopic point of view to simulate the morphological changes of ordinary water,magnetized water and magnetic-electrical coupled liquid droplets when they collide with coal dust particles.An automated and visible multi-factor coupling dust removal experimental platform was built to compare and analyze the dust removal efficiency of ordinary water,magnetized water and magnetic-electrical coupled aqueous solution from a macroscopic point of view.The results show that the droplets are easier to adhere to the surface of coal dust particles under the magnetic-electric coupling effect,and the spreading range is larger,and the covering range is extended by 44.98%.In addition,the decreases of the three kinds of solutions on dust,including total dust and dust deposition in descending order are as follows: magnetic-electric coupling solution > magnetized aqueous solution > tap water solution.In total dust,the dust removal efficiency of magnetic-electric coupling spray is 38.84 percentage points higher than that of tap water solution,and the dust removal efficiency reaches 91.2%.The dust removal efficiency of magnetic-electric coupling spray was 38.59 percentage points higher than that of tap water solution,and the dust removal efficiency reached 82.3%.更多还原