Fluids Inspired Granular Processing: Novel methods of mixing and separation

受流体启发的颗粒加工：混合和分离的新方法

• 批准号: 0933358
• 负责人: Joseph McCarthy
• 金额: $ 30万
• 依托单位: University of Pittsburgh
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0933358&HistoricalAwards=false
• 关键词: Fluids; Inspired; Granular; Processing; Novel

0933358 McCarthy Despite recent advances, particle processing still lags significantly behind its counterpart of fluid processing. The unifying theme of this proposal is the adaption of concepts from fluid processing in order to develop novel techniques for particle applications. Specifically, we target the mixing of dissimilar materials in surface flows of cohesionless (free flowing) materials as well as novel particle separation techniques. The underlying hypothesis of the first focus area of this work is that by exploiting flow perturbations a technique with a long history in fluid processing we can develop, for the first time, a general method for limiting particle segregation in free flowing systems, perhaps the most common and well studied of granular flows. The key to this approach lies in recognizing that it takes a finite time for material to segregate and that there is always a preferred direction that particles tend to segregate. In order to exploit these two facts, one needs to perturb the flow at a high frequency and in such a way that the surface layer is inverted. Particle separations techniques are typically quite low tech and often are energy intensive (e.g., sieving) or environmentally unfriendly (e.g., froth floatation) or both. The underlying hypothesis of the second focus area of this work is that we can develop rate based separations techniques based on granular temperature driven segregation and non-equipartition of (granular) energy. Specifically, we aim to build an analog of a granular chromatograph using a shaking table that imparts a gradient in vibration energy and hence, a gradient in granular temperature. Additionally, we plan to explore granular ratchets in analogy to Brownian ratchets from microfluidic studies because non equipartition of energy will yield the equivalent of the species dependent diffusion coefficient necessary for ratcheting to function for separations. These fluids inspired particle separations devices should not only overcome several of the shortcomings of traditional particle separations techniques, but also will help to validate kinetic theory based models in a very practical context. The chief intellectual merit of this work will be evidenced through advancing knowledge and understanding across fields of engineering and physics via: 1. Expanding our preliminary mixing results past the proof of concept stage and into a general methodology for limiting both single (density or size) and mixed mode segregation in a variety of surface dominated flows, including developing a set of validating experimental and simulation results that demonstrate the utility of flow perturbations for limiting segregation. 2. Establishing design heuristics for segregation free operation of a variety of particle processing devices. 3. A series of experiments that can be used as a test bed for variations on kinetic theory expressions. 4. Two novel particle separation devices: a granular chromatograph and a granular ratchet apparatus The primary broader impacts will be related to the economic impact on the wide variety of industries that deal with particle processing for whom mixing/segregation and particle separation have dramatic product/revenue implications. Additional broader impacts of the work lie in integrating teaching and research. This teaching/research integration will take two forms: training of two graduate students and several undergraduate researchers (with emphasis on under represented groups), and the development of a novel handson K-12 teacher training/partnership program focused on building interest in science in disadvantaged youths. Coupling a particle technology researchers natural propensity for hands-on instruction with a desire to have a positive impact on the the disadvantaged youth in the local community, the PI is proposing to form a partnership with the Academy Charter School (http://www.theacademysystem.com). This 8-12 grade school is the only charter school in the US exclusively focused on educating court ejudicated youth. Hands-on or inquiry based science education has been shown to not only improve student attitudes toward science, but also to foster higher overall achievement as well as a more flat response as a function of demographic background. The proposed partnership will comprise workshop like sessions between the PI and instructors in the Academy Charter School aimed at developing and/or adapting inquiry based educational modules suitable for science/engineering education in this unique learning environment highly competitive nature of the proposals submitted to the Program and the panel recommendation, the Program Director recommends that this proposal be awarded.

0933358 McCarthy尽管最近取得了进展，但颗粒处理仍然明显落后于流体处理。 该提案的统一主题是适应流体处理的概念，以开发颗粒应用的新技术。具体来说，我们的目标是在表面流动的粘性（自由流动）的材料，以及新的颗粒分离技术的不同材料的混合。这项工作的第一个重点领域的基本假设是，通过利用流体扰动的技术，在流体处理中有着悠久的历史，我们可以开发，第一次，一个一般的方法来限制颗粒分离在自由流动的系统，也许是最常见的和良好的研究颗粒流。这种方法的关键在于认识到材料分离需要有限的时间，并且总是存在颗粒倾向于分离的优选方向。为了利用这两个事实，需要以高频扰动流动，并且以这样的方式使表面层反转。颗粒分离技术通常是相当低技术的并且通常是能量密集型的（例如，筛分）或环境不友好（例如，泡沫浮选）或两者。这项工作的第二个重点领域的基本假设是，我们可以开发基于速率的分离技术的基础上颗粒温度驱动的偏析和非均分（颗粒）能量。具体来说，我们的目标是建立一个模拟的颗粒色谱仪使用摇床，赋予振动能量的梯度，因此，在颗粒温度梯度。此外，我们计划探索类似于布朗棘轮的颗粒棘轮从微流体研究，因为非均分的能量将产生等同的物种依赖的扩散系数所需的棘轮分离功能。这些流体激发的颗粒分离装置不仅应克服传统颗粒分离技术的几个缺点，而且还将有助于在非常实际的情况下验证基于动力学理论的模型。这项工作的主要智力价值将通过推进工程和物理领域的知识和理解来证明：1。扩展我们的初步混合结果过去的概念阶段的证明，并成为一个通用的方法，限制单一（密度或大小）和混合模式的偏析在各种表面为主的流量，包括开发一套验证实验和模拟结果，证明了效用的流量扰动限制偏析。2.为各种颗粒处理设备的无偏析操作建立设计理论。3.一系列实验，可用作动力学理论表达式变化的测试平台。4.两种新颖的颗粒分离装置：颗粒色谱仪和颗粒棘轮装置主要的更广泛的影响将与处理颗粒加工的各种行业的经济影响有关，对这些行业来说，混合/分离和颗粒分离具有显著的产品/收入影响。这项工作的其他更广泛的影响在于整合教学和研究。这种教学/研究一体化将采取两种形式：两个研究生和几个本科生研究人员（重点是代表性不足的群体）的培训，以及一个新的handson K-12教师培训/伙伴关系计划的发展，重点是建立在弱势青年科学的兴趣。耦合粒子技术研究人员的自然倾向动手教学的愿望有一个积极的影响，在当地社区的弱势青年，PI建议形成与学院特许学校的伙伴关系（http：www.theacademysystem.com）。 这所8-12年级的学校是美国唯一一所专门致力于教育法院判决的青少年的特许学校。实践或调查为基础的科学教育已被证明，不仅提高学生对科学的态度，而且还培养更高的整体成就，以及作为人口背景的功能更平坦的反应。拟议的合作伙伴关系将包括PI和学院特许学校的教师之间的研讨会，旨在开发和/或调整适合科学/工程教育的基于探究的教育模块，在这个独特的学习环境中，提交给计划和小组建议的提案具有高度竞争性，计划主任建议授予该提案。