【作者】 李郁；

【导师】 陈定方； 李勇智；

【作者基本信息】 武汉理工大学 ， 机械设计及理论， 2011， 博士

【摘要】 取料过程是影响散货连续装卸过程的重要因素,取料装置性能的优劣将直接影响散货连续装卸能力与效率的高低。论文研究一种新型的螺旋气力吸取料机,该装置结合了垂直螺旋输送与负压气力输送技术,能够快捷、高效地完成从料堆取料及实现气固分离的动作,兼具负压气力输送自动取料、清偿量低和垂直螺旋生产率高的优点。螺旋气力吸取料机结构由三个区段构成：倒锥体离心分离段、垂直螺旋提升段、稀相气密输送段。在负压作用下,物料从进料口被具有一定速度的空气流携带入倒锥体；由于空气流随着气流速度的减小而丧失携带物料的能力,物料颗粒与气流发生分离,同时,在螺旋叶片的作用下,贴紧管壁做螺旋上升；经过垂直螺旋提升的物料流从卸料口流出；含有极少量残余物料的稀相空气流沿螺旋中心孔向上方经风管排出,经除尘器进入风机。通过本文的研究,取得了如下成果：1.为论证螺旋气力吸取料机方案的可行性,建立了螺旋气力吸取料机的试验台,并进行了大量的实验研究；试验表明螺旋气力吸取料机是一种快捷高效的取料装置,能够实现散货物料的自行取料,以及气固二相流的高效分离。2.建立了临界分离粒径的数学模型,分析了临界分离粒径与螺旋的结构尺寸、螺旋转速、气流速度和物料密度,颗粒粒径之间的关系,为螺旋气力取料装置的设计提供了理论依据；3.建立了分离界面的数学模型,对气固二相流在螺旋槽中的运动规律进行分析,推算出物料的运动方程和气体速度方程；4.确定了空气流临界速度的求值区域,使之既满足负压自行取料,又能保证物料从气固二相流的有效分离；5.确定了物料从气固二相流中分离出来的终端速度,这个终端速度决定了它是被叶片捕集还是被气体带走。颗粒在离心力作用下克服阻力,被向外甩并以相对于气体的终端速度运动；6.分析了螺旋气力吸取料机分离过程的各个变量,采用量纲分析法导出了试验模型的相似准则,为精确预测螺旋气力吸取料机的分离性能提供了依据。螺旋气力吸取料机具有自行取料,高效率,低清仓量等多种取料优良特性。采用此种取料方式提取物料,可使气力输送分离问题、散货物料装卸设备自行取料问题以及清仓问题等一并得到解决,为散货物料装卸工艺的新方案设计提供了条件,这也将是散货连续卸船技术的一个发展方向。更多还原

【Abstract】 With more and more share the bulk cargo occupying in the world’s whole freight volume, the conveying efficiency receives more and more attention. While among the whole bulk conveying process, how to effectively and conveniently put the bulk into the conveying process is one of the most important key problems. The article gives a good solution by providing with a brand-new equipment—Screw-gas Bulk Sucking and Taking Equipment, which applies both the theory of vertical screw conveyor and the theory of pneumatic handling.Screw-gas Bulk Sucking and Taking Equipment constitutes of 3 parts. Respectively from bottom to above they are:Centrifugal force Separating Part, Screw Lifting Part and Pneumatic Conveying Part. Granular material is drawn into the equipment in the form of gas-solid two-phase flow by the Atmospheric pressure, and then helically rises in the Centrifugal Force Separating Part which is an inverted cone. The material would be separated from the two-phase flow by the effect of centrifugal force and then be lifted in the Screw Lifting Part. The gas flow with the very little remained material would be drawn into the blower. By thus Screw-gas Bulk Sucking and Taking Equipment could take the material and put it to the next conveying process conveniently and efficiently with the superiorities of low clearing-up, little dust removal, simple construction and convenient maintenance.The following results have been achieved:1. The feasibility of this Screw-gas Bulk Sucking and Taking Equipment was demonstrated; the test bed for this device has been established and a lot of experimental researches based on it were conducted. Tests proved that this feeding device could be a good choice, which could realize self-feeding and separating gas-solid two-phase with high effectiveness and efficiency.2.The mathematical model of the critical separating-particle size in the flow was established; and based on it, how the critical particle size could be affected by the size of the device, the spiral speed, the air-flow entering speed and the material density was analyzed. Thus provides a theoretical base for the design work;3.The mathematical model of the separating interface of gas-solid two-phase flow was established and the flowing movements of the material and the gas were analyzed, determining the equation of material motion and gas speed equation;4. The critical gas entering speed was determined by giving a certain range, enabling it to suck the material with enough speed, and also to ensure that the material be separated from the gas-solid two-phase flow;5.The terminal velocity of the material flow separated from the gas-solid two-phase was determined, which could determine the material to be captured by screw leaves or taken away by the gas. Particles under the centrifugal force will overcome the resistance, and thrown out, flowing with the terminal velocity relative to the movement;6. A comprehensive analysis of all the possible variables in the separation process was finished, using dimensional analysis method to achieve the test model criteria, which provides the basis for the accurate prediction of this Screw-gas Bulk Sucking and Taking Equipment separation performance.Screw-gas Bulk Sucking and Taking Equipment own the advancement of self-feeding, high efficiency, low clearance and many other advantages. By applying this device, the problems of separating in pneumatic conveying, self-feeding in bulk material handling, and clearance issues could all be resolved, which provides conditions for the possible new effective plans of the bulk material handling processes, and it could be a new trend for the unloading bulk technology development.更多还原