【作者】 崔岩；

【导师】 葛晓陵；

【作者基本信息】 华东理工大学 ， 化工过程机械， 2011， 博士

【摘要】 气流粉碎工艺是制备超细粉体的一种重要方法,在超细粉体制备领域发挥着重要作用。在气流粉碎工艺过程中,对不同种类的物料,粉碎情况都不相同,粉碎加工过程的多项参数对粉碎结果都有影响。目前气流粉碎工艺的很多研究尚处于初级阶段,还没有一台气流粉碎机可以实现面对所有物料颗粒进行粉碎的功能。本文将计算机可视化仿真技术引入气流粉碎工艺当中,把两门学科结合起来,建立起对多种粉体具有普适性的气流粉碎碰撞过程的计算机仿真系统,在一定程度上为以后的研究提供了理论和实践基础。本文首先对气流粉碎工艺和计算机仿真技术的发展进行了介绍,介绍了气流粉碎和计算机仿真技术的一些基本概念和基础理论。提出并证明了了气流粉碎过程中的粉体行为符合分形理论要求,粉体在粉碎过程中的行为可以用分形理论加以描述的观点,并在传统能量判别理论的基础上结合分形理论和有限元数值分析技术,建立起气流粉碎过程的仿真计算系统,以达到粉碎操作的最优化、粉碎过程的可视化的效果。本文提出了气流粉碎过程的仿真计算系统的建立方法,建立了靶板式、流化床式和扁平式三种气流粉碎机的粉碎仿真分析计算模型。这些模型对于粉碎过程中的各种粉体系统具有一定的普适性。确定了粉碎过程数值模拟的具体方法,并运用ANSYS软件的LS-DYNA系统模拟计算了靶板式、流化床式和扁平式三种气流粉碎机的粉碎工况。通过仿真实验研究确定了不同粉碎物料粉碎粒径与进料速度、分形维数之间的数学关系,得出三者的函数关系。提出在计算过程中可用速度比代替颗粒数量百分比,即用整体速度的降低代替部分颗粒的速度丧失,经实验证明与实际粉碎效果相同。提出了气流粉碎过程的仿真显示系统的建立方法,运用分形理论描述了粉体在粉碎过程中的聚团行为。运用3DS MAX建模软件按实际比例建立了靶板式、流化床式和扁平式三种气流粉碎机的粉碎仿真显示模型。建立了对不同类型的粉体颗粒的材质库。将仿真计算结果与实际粉碎结果进行比较后,分析了仿真系统对于不同类型粉体的适用情况及计算误差的产生原因。通过仿真计算结果与实际粉碎结果的比较,确定了不同粉体的仿真计算误差范围。得出多种用数学方法不能计算的有机粉体的破碎功经验值,并存储了十几种材料的粉碎经验参数。更多还原

【Abstract】 Jet milling process is an important method of ultra-fine particle preparation, which plays an important role in the ultra-fine particles preparation field. For different types of material,the milling cases are different as a number of parameters of the milling process have an impact on the milling results. Most research on the jet milling process is still in its infancy and there is still not a single jet milling which is capable of dealing with all kinds of particles at present. Through introducing the computer visual simulation technology into the jet milling process, a computer visual simulation system of jet milling process is built which is universal to various kinds of materials; Furthermore, to some extent, both theoretical and practical basis for the future research is also provided.First of all, the paper introduced some basic concepts and theories of jet milling process and computer simulation technology. It put forward and proved that the particle behavior in the jet milling process is consistent with the fractal theory, and the particle behavior in the jet milling process can be described by the fractal theory. In order to realize optimized effects of jet milling operation and visualization grinding process, a computer simulation system of jet milling process is built based on the traditional energy theory and finite element analysis technology, combined with the fractal theory.A methodology of the establishment of a jet milling process computer simulation system is also proposed in the paper, including three types of analysis models of jet mill process:target plate type, flow bed type and flat type. These models have a certain degree of universality to the materials in jet milling process. The specific analysis methods of jet milling process is determined, and three types of jet milling machines, i.e. target plate type, flow bed type and flat type are analyzed with the LS-DYNA system featured ANSYS software.After research on simulation experiments, the mathematical relationship between the particle size, grinding feed rate, and the fractal dimension of different kinds of materials is researched, and equations among the three are concluded. The paper put forward that the percent of particle number could be replaced by the velocity ratio, i.e. the rate loss of part particles could be replaced by the rate loss of the whole particle flow in proportion and the result is proved through experiments. A methodology of the establishment of a simulation display system of the jet milling process is proposed; in addition, aggregation behavior of particles in jet milling process is described with the fractal theory in the paper. Simulation display models of target plate type, fluidized bed type and flat type of jet milling are established with 3ds-max software, and a material library consisting of different kinds of material particles is established. After a comparison between simulation results and the actual grinding results, the applicability of the simulation system for different kinds of particle and the reason why a calculation error occurred is analyzed. Through the comparison, the error range of calculation for different kinds of materials, a variety of experience values of broken work for different kinds of particles, and dozens of empirical parameters are all concluded.更多还原