气水喷嘴雾化特征与降尘效果分析

为提高气水喷嘴在煤矿井下高浓度粉尘作业场所的喷雾降尘效率,通过实验研究了气水喷嘴的雾化特性参数,得出了雾滴平均直径与气、水流量的变化规律;以煤矿综掘工作面气水喷雾降尘过程为研究对象,建立了相应的数学模型,推导出了气水喷嘴降尘效率的关系式,采用Matlab软件绘制了降尘效率曲线.研究表明:水流量一定时,气体流量越大降尘效率越大;气体流量一定时,降尘效率随水流量的增大先增大后减小;粉尘粒径越大,喷雾雾滴有效作用距离越长,粉尘越容易被沉降;要使气水喷嘴的降尘效率达到80%以上,气体流量必须大于150×10~(-5)m~3/s,最佳的气水流量比范围为100~150.依据工作面粉尘的粒径分布和降尘效率要求,参照相关曲线选择最佳的气水流量,可以达到更好的降尘效果和经济效益.     

提高湿法烟气脱硫喷淋塔脱硫和除尘效率的探讨

分析了现代大型喷淋塔为提高脱硫与除尘效率在设计上所作的改进及存在的问题。通过一个曾经设计过的喷淋塔实例,结合烟气和吸收液两相逆向流动和两相间的化工传质过程,剖析了喷淋层覆盖率的实质,提出弱效喷淋覆盖和多重喷淋覆盖对喷淋塔脱硫和除尘效率的影响,给出喷淋覆盖率的选择、喷淋层和喷嘴布置的设计方法,对改善烟气脱硫和除尘效率均有明显效果。     

Effects of atomization parameters of dust removal nozzles on the de-dusting results for different dust sources

In order to obtain appropriate spray pressure and enhance the spraying and dust removal efficiency, various factors including the dust characteristics, nozzle spraying angle, effective spraying range, water consumption and droplet size are taken into account. The dust characteristics from different mines and atomization parameters of different pressure nozzles were measured. It was found that the internal pressure of coal cutters and roadheaders should be kept at 2 MPa, which could ensure large droplet size, large spraying angle and low water consumption and hence realizing a large-area covering and capture for large particle dusts. However, the external spray pressure should be kept at 4 MPa for smaller droplet size and longer effective spraying range, leading to effective dust removal in the operator zone. The spray pressure of support moving, drawing opening, and stage loader on a fully mechanized caving face and stage loader on a fully mechanized driving face should be kept at 8 MPa, under which the nozzles have long effective spraying range, high water flow and small droplet size for the rapid capture of instantaneous, high-concentration and small size dust groups. From the applications on the caving and driving faces in the coal mines, it is indicated that the optimization of spray pressure in different spraying positions could effectively enhance dust removal efficiency. Selecting appropriate nozzles according to the dust characteristics at different positions is also favorable for dust removal efficiency. With the selected nozzles under optimal pressures, the removal rates of both total dust and respirable dust could reach over70%, showing a significant de-dusting effect.     

电极化在电收尘器中的作用

先分析了极化尘粒在均匀场和非均匀场中受到的梯度力情况,然后分析了极化尘粒在均匀和非均力场中的静电凝聚行为。分析表明,在非均匀场中,极化尘粒可受到较大的梯度力并可导致显著的凝聚效果。实验结果证实了极化可显著提高收尘效率。最后指出其应用前景。     

脉冲电源对静电除尘性能影响的实验与理论研究

以国内某燃煤电厂320 MW机组双室五电场干式静电除尘系统为对象,对4组不同电源工况条件下的除尘特性进行了实验研究. 探讨了脉冲电源对静电除尘性能的影响,进一步深入分析了不同电源工况对分级除尘效率的影响. 结果表明,4种电源工况下的实验的静电除尘系统对于燃煤电厂飞灰的除尘效率均可超过 99.79%. 对比实验发现,高压脉冲电源不仅大大降低能耗,而且可显著提高对微细粉尘的捕集效率,颗粒越小差异越显著. 适当提高工作电压,增大荷电强度,使飞灰颗粒荷电充分,提高了电场驱进力,飞灰的捕集效率提高.     

Dust removal efficiency of high pressure atomization in underground coal mine

To master theoretical calculation for dust removal efficiency of high pressure atomization in an underground coal mine, the corresponding atomization characteristics and dust removal efficiency were both comprehensively studied in theory by virtue of related theories of hydromechanics and aerosol.According to actual measurements of flow coefficients and atomization angles of X-type swirl nozzle,computational formula was derived for atomized particle sizes of such a nozzle in conjunction with relevant empirical equation. Moreover, a mathematical model for applying high pressure atomization to dust removal in underground coal mine was also established to deduce theoretical computation formula of fractional efficiency. Then, Matlab was adopted to portray the relation curve between fractional efficiency and influence factors. In addition, a theoretical formula was also set up for removal efficiency of respirable dust and total coal dust based on dust size and frequency distribution equations. In the end,impacts of dust characteristic parameters on various dust removal efficiencies were analyzed.     

TQLZ自衡振动筛的静力与模态分析

以自衡振动筛为研究对象,利用SolidWorks软件,对自衡振动筛进行了有限元建模及静力分析、模态分析,分析结果为振动筛的优化设计提供理论依据.     

综放面多尘源粉尘分布规律数值模拟及实测

为解决综放工作面粉尘浓度高的问题,掌握各作业工序粉尘浓度空间分布规律,有效指导粉尘控制工作,依据气固两相流理论,运用Fluent软件对综放工作面割煤、移架、放顶煤、转载各工序单独及同时作业时的粉尘分布规律进行数值模拟,并与现场实测数据进行对比分析.结果表明:割煤作业粉尘沿采煤机机道扩散的同时向人行道空间扩散,需在滚筒尘源处控尘,并在采煤机外侧采取水幕帘除尘措施;移架作业时人行道粉尘浓度高于机道粉尘浓度,需在机道空间和人行道空间均设置架间喷雾;放煤作业粉尘沿人行道空间分布较大,需在放煤口采取隔尘措施;转载点局部风速大,粉尘影响范围较广,应采取密封等措施.还应在放煤和割煤作业之间增加全断面喷雾降尘装置.     

荷电水雾除尘的性能研究

选择适于水雾荷电的单相雾化喷咀，采用感应荷电法对雾滴荷电规律和水雾除尘效果做了系统测试，并分析了该方式下系统的几何、运行、电气等参数对雾滴荷电程度的影响。     

香蕉形直线振动筛疲劳分析

以4090香蕉形直线振动筛为分析对象,考虑铆钉联接对结构性能的影响,采用多点约束方法处理铆钉联接,建立有限元模型,对施加最大荷载时的振动筛做静力学分析,得到最大应力分布,确定结构最危险部位。考虑应力集中、疲劳缺口、尺寸、表面状态、加载方式等因素对结构疲劳寿命的影响,对材料的s-n曲线进行修正。在静力学分析结果的基础上,结合修正后的s-n曲线,对结构进行疲劳分析,最终得到振动筛疲劳寿命.     

Fault tree analysis of dust suppression mechanism in a spray system with wetting agent

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直线振动筛模态分析及起制动过程分析

运用振动理论对直线振动筛进行了模态分析及起制动过程分析，在设计阶段，通过系统的动力学特性分析可以修改某些可变参数，使振动筛的运动处于最佳状态，从而提高筛分效率和生产能力，同时使系统的动载荷减小到最低限度，提高振动筛的强度和使用寿命对于现有的直线振动筛，特别是存在某些问题或出现了故障的振动筛进行动力学特性分析，可以找出由于系统参数不合理而造成的问题，并提出改进设计的有效方案．在此理论分析和现场实测数据的基础上编制了相应的计算机程序，从而为提高振动筛的设计水平打下了基础．     

香蕉型振动筛静力学与固有特性有限元分析

采用参数化建模方法建立振动筛的有限元模型,对其进行模态分析和静力学分析,计算出筛箱结构的固有频率、固有振型、应力分布,为振动筛动力学计算和优化设计提供依据.     

线管式热电子发射高温静电除尘器的数值研究

热电子发射式高温静电除尘技术是一种新颖的高温烟气净化方法,与传统的电晕式静电除尘技术不同,其以稀土钨制成的阴极在高温下发射电子的方式使烟气中的粉尘荷电,然后依靠电场力的作用将其捕集. 本文建立了线管式热电子发射式高温静电除尘器除尘过程数学物理模型,模型涵盖了颗粒荷电方程和颗粒浓度场. 利用MATLAB编写粉尘荷电量和除尘效率的计算程序,并进行数值计算,得到不同条件下粉尘荷电量和除尘效率,系统地研究了各种影响因素与除尘效率的关系,发现降低烟气进口流速、提高温度及收尘电压、减小除尘管半径,都可以提高除尘效率.     

Multi-phase computer modeling and laboratory study of dust capture by an inertial Vortecone scrubber

Dust generated in mining and tunneling activities is hazardous to health of persons and safety of operations. These projects employ pick-milling machines to extract minerals and rock by mechanical breakage.The machines are equipped with flooded-bed scrubbers that encase dust particles within fine water films as particles encounter a flooded wire-mesh screen. A major disadvantage is that the screen gets clogged when particles become trapped within the wire mesh, reducing airflow through the scrubber and increasing ambient dust concentrations. Thus, the system requires frequent maintenance or replacement. The application of a Vortecone scrubber as an improved alternative to conventional fibrous type scrubbers is investigated. A Vortecone forces dust-laden air and water to follow a complex, rapidly swirling motion.The momentum drives dust particles towards the periphery where they are captured by the water film.The operating characteristics of a reduced-scale physical model of a Vortecone, with its primary axis mounted in the horizontal orientation, was analyzed numerically and experimentally. Computational fluid dynamics(CFD) models depicting the spraying action and multi-phase air/water flows using the volume of fraction(VOF) approach, are presented. Experimental results, utilizing an optical particle counting technique to establish the dust-cleaning capabilities of the model, are also described.     

Controlling the coal dust at transshipment point: A study of the foam-sol foaming device

In order to effectively control the dust at the transshipment point with foam-sol, this paper attempted to study the characteristics of dust diffusion at transshipment point and the foam-sol foaming device with diffusion outlet was also designed in this paper. To study the diffusion rules of coal dust, fluent discrete phase model was utilized in the numerical simulation, as the coal dust was thrown down at a horizontal velocity of 2.5 m/s. A foam-sol foaming device was designed, through which foaming agent could be automatically sucked into the Venturi by the negative pressure. The automatic controller was also equipped, which could transform the energy of the compressed air into the constant pressure difference so that the gelling agent could be qualitatively added into the gel container. The diffusion outlet that could spray out foam-sol in a continuous, conical and 3D manner was also designed. Moreover, this paper also carried out the contrast experiments on dust removal efficiency among water, aqueous foam and foam-sol. The results clearly show that the symmetrical whirlpools appeared below the inlet where the largest whirlpool diameter was 0.52 m, and the horizontal distance from swirl range to the inlet was approximately 0.69 m. By using the self-designed foaming device, the foaming was multiplied by 30 times and the volume ratio with water and foaming agent reached 95%:5%. In this context, the gas pressure was controlled at 0.3 MPa, with gas flow at 15 m³/h and water flow at 0.5 m³/h, with water pressure controlled between 0.34 and 0.36 MPa. The foam-sol has the highest dust removal efficiency than other agents.     

直线振动筛筛分效率与生产率的试验研究

在正交试验的基础上研究了自同步直线振动筛的筛分效率与生产率的变化规律，找出了各种参数的最佳组合方案，为改进该种振动筛的设计参数，提高生产能力提供了有益的参考。     

计算网格对柴油机喷雾数值模拟的影响

利用通用商业CFD软件STAR-CD对柴油机喷雾特性进行数值模拟,分析了计算网格对柴油机喷雾数值模拟结果的影响。研究表明,计算网格的划分直接影响到气流运动状态和油束的几何形态。随着网格加密,喷雾射流速度不断增大,喷雾油束几何形态变得细长,喷雾贯穿距增大。将Hiroyasu经验公式算出的喷雾贯穿距与CFD数值模拟值进行对比,说明采用网格D模拟计算的值吻合较好,该网格适合于喷雾计算。     

灵武煤制水煤浆颗粒级配研究

根据颗粒堆积模型,探讨了粒度分布对水煤浆成浆性能的影响.用GZS-1型标准振筛机将煤样筛分成60～140目、140～200目及200目以上3种.采用干法制浆,配制了理论质量分数为65%的浆体,分别考查了各区间粒度组分数对浆体成浆性能的影响规律.结果表明,200目以上颗粒质量分数为30%,140～200目颗粒质量分数为30%,60～140目颗粒质量分数为40%时制得的水煤浆黏度最低,为497.0 mPa.s.     

基于ANSYS高频脱水筛性能的分析研究

文章利用Pro/Engineer软件对高频脱水筛进行了力学模型建模,并运用ANSYS软件建立了该振动筛的有限元模型。通过对振动筛的静力学分析计算,获得了筛箱在工作过程中的应力分布规律。对振动筛的工作过程进行了详细的分析研究,并确定了高频脱水筛工作过程中的危险区域,进而对筛子的结构系统进行了优化设计,为确保高频脱水筛设计和安全使用提供了可靠的技术参数。