Multidimensional Problems in Granular Plasticity

颗粒塑性的多维问题

• 批准号: 9802520
• 负责人: E Bruce Pitman
• 金额: $ 1.66万
• 依托单位: SUNY at Buffalo
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-08-01 至 2000-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9802520&HistoricalAwards=false
• 关键词: Multidimensional; Problems; Granular; Plasticity

DMS-9802520 Pitman This interdisciplinary proposal addresses scientific issues regarding the dynamics of granular materials coupled with interstitial fluid. The investigation is composed of three parts: modeling, analysis, and numerical computation. Models of particle-fluid motion must determine which physical mechanisms are dominant and which may be neglected without detrimental effect. In particular, traditional models of these flows treat the particle phase as a fluid-like material with a viscosity that depends on the particle volume fraction. A significant component of this research program is to study the effects of modeling the particle phase as a frictional material. Analysis will be primarily directed toward a study of the stability of distinguished solutions to the model equations. Numerical simulations will provide an understanding of nonlinearity in the equations, especially the effect of the particle phase model. These complementary methods of investigation will be guided by recent experiments that highlight the need for a new approach to the question of particle-fluid interaction. The combined flow of particles and fluid has many industrial applications, such as particle coating and drying, particle flow in pressurized vessels and cat-crackers, transport by lubrication, and heat transfer. New xerographic and metallurgic technology necessitate very fine powders. In these latter applications, however, as particle size decreases, transport and handling become more difficult, and the effects of interstitial gas become more important. Without better characterization of particle-fluid flows, products that exploit new technologies may not come on-line as quickly, nor with sufficient reliability. In this regard, it is useful to note a study by the Rand Corporation showing that, because of an inability to accurately predict powder behavior, solids-producing manufacturing plants performed on average at 63% of design capacity, compared to 84% for liquids-producing plants . This project will study new mathematical models for the behavior of very fine powders. The results of this project will be compared with concurrent experimental work by industrial researchers.

DMS-9802520 Pitman这个跨学科的建议解决了有关颗粒材料的动力学的科学问题，结合了间隙流体。 研究由三个部分组成：建模，分析和数值计算。 颗粒流体运动的模型必须确定哪些物理机制是主导的，并且可以忽略哪些物理机制而不会造成不利影响。 特别是，这些流的传统模型将粒子相视为流体样材料，其粘度取决于粒子体积分数。 该研究计划的重要组成部分是研究将颗粒相作为摩擦材料建模的效果。 分析将主要针对对模型方程的稳定性的稳定性研究。 数值模拟将提供对方程中非线性的理解，尤其是粒子相模型的效果。 这些互补的研究方法将由最近的实验指导，这些实验强调了对粒子流体相互作用问题采用新方法的必要性。 颗粒和流体的组合流具有许多工业应用，例如颗粒涂层和干燥，加压血管和猫式脱带式的颗粒流，通过润滑进行运输以及传热。 新的Xerographic和冶金技术需要非常优质的粉末。 但是，在这些后一种应用中，随着粒径降低，运输和处理变得越来越困难，并且间质气体的影响变得越来越重要。 如果没有更好地表征粒子流体流的表征，那么利用新技术的产品可能不会迅速出现，也不会具有足够的可靠性。 在这方面，注意到兰德公司的一项研究表明，由于无法准确预测粉末行为，因此产生固体的制造厂平均以设计能力的63％进行制造厂，而生产液体生产工厂的制造厂则为84％。 该项目将研究针对非常优质粉末的行为的新数学模型。 该项目的结果将与工业研究人员的同时实验工作进行比较。