【作者】 刘雨；

【导师】 侯运丰；

【作者基本信息】 兰州理工大学 ， 机械设计及理论， 2008， 硕士

【摘要】 本文以湍流式超细粉碎机为研究对象,利用该机制取了几种材料的亚微米级超细粉体。课题的研究目的是利用实验与理论分析相结合的方法对影响粉碎效果的因素进行分析。在此基础上,利用模型分析的方法对粉碎机的工作机理进行了探讨,为进一步优化粉碎机结构参数、改进结构提供了理论支持。首先,介绍了与本课题有关的国内外气流粉碎设备和粉碎理论的发展现状。利用均匀设计的方法对几种中药材进行了多因素、多水平超细粉碎试验,并且结合实际情况对工艺参数进行了系统的分析,得出了在试验条件下的最佳工艺参数。试验结果表明,各因素对粉碎效果的影响有一定差别。叶轮转速的提高和粉碎时间的延长是造成粉体团聚的主要原因。在一定的加料质量水平下,每个叶轮转速水平都存在着一个团聚时间,随着叶轮转速的提高,团聚时间呈现缩短趋势。作者还对粉体的团聚机理进行了剖析。其次,作者对目前气流粉碎机的各种数学模型进行了仔细分析。结合湍流式超细粉碎机的实际情况,建立起了基于化学反应速率理论的粉碎动力学模型和基于不可逆热力学过程的粉碎动力学模型,并且进行了实验验证。结果表明,基于化学反应速率理论的粉碎动力学模型与本机的实验数据吻合的比较好,因此,可以将这一模型作为以后对粉碎机进行进一步研究的理论依据。为了研究粉体粒子在粉碎机内的运动规律,建立了基于扩散理论的粉碎与传输模型,为实现多参数,多目标工艺优化打下了理论基础。为了改进粉碎机的结构设计,作者还建立了粉碎机的相似模型,从而为机器的大型化设计和工业应用提出了研究方向。更多还原

【Abstract】 Pulverizer of turbulence was researched in this thesis, by which several material’s submicron superfine powder were prepared. The purpose of this assignment is to analyze the reasons effecting result by the experimental means and theory means. Based on these achievements, the working mechanism of the pulverizer of turbulence was analyzed, which will provide a theory support for parameters’ optimization and structure’s improvement.First, the up-to-date theory about jet mill and comminution technology were introduced in this thesis. The multivariate and multilevel crushing experiments based on uniform design were conducted, regarding several kinds of traditional Chinese medicine as experimental material. In the same time, optimizations effecting result were analyzed systematically, and then the optimal optimizations in the experiment were obtained. Experiments were performed to validate that the contribution of each factor to the result was distinct. The increasing of impeller’s rotative speed and the working time’s extension are major reasons that cause the powder’s polymerization. When the mass of the experimental material is defined, every speed of impeller’s rotative speed corresponds with a polymerization time. By the increasing of the impeller’s rotative speed, the corresponding polymerization time descends. The author also analyzed the mechanism of superfine powder’s polymerization.Second, the author has researched the mathematical models of jet mill carefully. And then the dynamics model based on chemical reaction rate and irreversible thermodynamic process were established. Meanwhile, the author also verified the two model by experiments, which showed that the dynamics model based on chemical reaction rate fitted the test data perfectly. So this model can be the theoretical basis for the further research. In order to study the motion law of particles inside the machine, the crushing and transmission model based on diffusion theory was established, which has made a theoretical basis for the multi-parameter and multi-objective optimization. In order to improve the machine’s structure, a model based on similarity theory was established, which has brought up the research direction for the machine’s enlargement design and application in the industry.更多还原