Assessing Stress Conditions and Impact Velocities in Fluidized Bed Opposed Jet Mills (Open Access)
Alexander Strobel, Benedikt Köninger, Stefan Romeis, Florian Schott, Karl-Ernst Wirth, Wolfgang Peukert*
Keywords: Fluidized bed opposed jet mill; Single particle probes; Finite element modeling; Stress number distribution; Relative velocity distribution
DOI: 10.1016/j.partic.2020.02.006
文章概述
本文利用金属铝的延展性特点，结合有限元计算及图像分析，巧妙地将铝颗粒表面的形变与颗粒间相对速度和碰撞频率相关联。通过对铝颗粒表面形变的研究，定量评估流化床对冲式气流磨中颗粒间的撞击速度和应力分布。
亮点导读
※ Characterization of fluidized bed opposed jet mills by single particle probes.
※ Determination of relative particle velocities and effective stress numbers.
※ Proposed approach validated by particle image velocimetry during secondary gas injection into a fluidized bed reactor.
内容简介
流化床对冲式气流磨因其冲击强度大，磨损小，对产品无污染等特点，被广泛用于高纯度、热敏产品如活性医药原料药、营养素、颜料染料、磨料陶瓷等的生产和加工。该气流磨的粉碎机理是从喷嘴高速喷出的气流束在磨内形成对心逆喷射流场，磨内固体颗粒在压差作用下流化、加速并在射流的交汇点产生剧烈碰撞、摩擦而粉碎。因此，其性能主要受颗粒的运动情况、撞击速度及应力分布影响，但迄今为止相关定性研究少有报道。
德国埃尔兰根-纽伦堡大学颗粒技术研究所Wolfgang Peukert教授团队对流化床对冲式气流磨的应力条件和冲击速度进行了深入的研究，文章中提出了一种独特的方法，即将混有少量金属铝颗粒的玻璃微球加入磨床，在床内的运动过程中，两种颗粒的相互作用将使铝颗粒表面发生形变，产生凹痕，凹痕的大小及数量与颗粒间的相对速度、碰撞频率以及应力分布密切相关。这种关系可以用有限元方法对单个探针颗粒的应力应变行为计算得出并结合SEM中的纳米压痕及粒子图像测速仪进行验证。通过这种方法，作者首次根据过程参数定量确定了磨机内应力分布情况，同时，进一步对不同的固体浓度和气压条件下的应力情况进行了测试。
上述方法适用于对各类磨机中的过程进行研究，为磨机的机理研究和定量放大开辟了新途径。
作者介绍
研究方向：纳米技术、产品设计和配制技术、界面科学和机械工程等
Wolfgang Peukert studied chemical engineering at the University of Karlsruhe, where he obtained his Ph.D. After 7 years in industry he held a full professorship at the Technical University of Munich (1998-2003). Since 2003 Wolfgang Peukert is the head of the Institute of Particle Technology (LFG) at the Friedrich-Alexander University of Erlangen-Nuremberg. He was coordinator of the Erlangen Cluster of Excellence “Engineering of Advanced Materials” (2007-2019) and currently coordinates the collaborative research center “Design of Particulate Products”. He has published more than 400 papers in scientific journals and books.
研究方向：两相流流体力学性质、传热及化学反应
Karl-Ernst Wirth is a retired professor of mechanical engineering (particle technology) from the Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) at Erlangen, Germany. He studied chemical engineering (specialization food technology) at Karlsruhe Institute of Technology (KIT) and completed his doctorate in 1980 in the field of pneumatic conveying at the FAU. He received his habilitation in the field of vertical fluid-solid flows from the FAU and was appointed professor in 1991. For more than 10 years he was chairmen of the multiphase flow group of the German Association of Chemical Engineers. His research was recognized by the German Association of Chemical Engineers (GVC) with the Arnold-Eucken-Award and the Hans-Rumpf-Medal.
研究方向：不同类型球磨机和分级磨的应力条件的实验表征等
Alexander Strobel studied life science engineering at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) and graduated with his master degree in 2015. Until the end of 2019 he was a doctoral researcher (scientific coworker) at the Institute of Particle Technology (LFG) in Erlangen, Germany, in the comminution group of Prof. Wolfgang Peukert.
研究方向：先进流化床反应器、分级磨和多相流测量技术(如X射线层析成像技术)等
Benedikt Köninger works since 2018 as a process developer at Wacker Chemie AG in the business unit Polysilicon. He studied chemical and biological engineering at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) and graduated 2013 with his master degree. Until 2018 he worked as a Ph.D candidate (scientific coworker) in the multiphase flow group of Prof. Karl-Ernst Wirth, located at the Institute of Particle Technology (FAU).
研究方向：颗粒形貌控制和构效关系，微粒的机械性能等
Stefan Romeis studied material science and chemical engineering at the Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), and obtained his Ph.D in the field of comminution and micromechanics. After graduation Stefan worked at the Institute of Particle Technology (LFG) as scientific coworker with Prof. Peukert. Furthermore, Stefan developed a methodology to assess stressing conditions in different comminution devices. In 2019 Stefan joined the R&D department of Saint Gobain.
研究方向：利用探针颗粒研究流化床对喷式气流磨中的应力条件等
Florian Schott works as an Application Engineer for consumer products at Dr. Wack Chemie GmbH in Ingolstadt. He studied chemical engineering and got his master degree in 2018 at the Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU). During this time, he helped to set up a mobile laboratory gasifier.
供稿：原文作者
编辑：《颗粒学报》编辑部