Coupling Tribocharging and Hydrodynamics in Fliuidized Beds

流化床中摩擦起电和流体动力学的耦合

• 批准号: 1601986
• 负责人: Sankaran Sundaresan
• 金额: $ 39.3万
• 依托单位: Princeton University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-01 至 2020-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1601986&HistoricalAwards=false
• 关键词: Coupling; Tribocharging; Hydrodynamics; Fliuidized; Beds

CBET - 1601986PI: Sundaresan, SankaranTribocharging refers to the exchange of electric charge between two materials that make mechanical contact with each other. It is observed in many situations involving flows of particles suspended in a gas. One industrially important example is tribocharging in a fluidized bed chemical reactor. In this kind of reactor, gas flows through a bed of particles at such high rates that the particles become "fluidized," and the particles and gas behave as a fluid mixture. This project seeks to understand how tribocharging affects the fluid dynamics of gas-particle suspensions. Models will be developed to explain and predict how the dynamics of tribocharging and hydrodynamics of gas-particle suspensions are affected by material characteristics, humidity, and particle size. The research will be the first study that focuses specifically on the coupling between tribocharging and fluidization hydrodynamics. The results will be useful in a wide range of industrial processes involving gas-solid suspensions, because tribocharging can create significant hazards and reduce process efficiencies. The project will provide opportunities for students at various academic levels to participate in research, including high-school students who participate in Princeton's summer Laboratory Learning Program.The goals of the project are to develop and validate a computational model that accounts for tribocharging and electrostatic forces in fluid-particle flow systems, to understand how electrostatics affect hydrodynamics, and to understand the transient rate of charging in these systems. The model will use an effective work function for triboelectric charging that captures charge transfer owing to differences in material of contacting particles, differences in overall charge of contacting particles, differences in sizes of the contacting particles and humidity. The effective work function will be incorporated into a model that combines a discrete element method for resolving particle contacts with computational fluid dynamics for resolving larger scales of the flow. Model parameters will be calibrated using vibrated bed experiments. Then, the model's predictions of fluidized bed dynamics will be tested against experiments in which particle material, size, humidity and the wall material of the fluidized bed are systematically varied. Results of the study will provide useful information for industrial practitioners to improve processes involving granular materials.

摩擦充电是指两种材料之间的电荷交换，使彼此产生机械接触。在许多涉及悬浮在气体中的颗粒流动的情况下都可以观察到它。一个工业上重要的例子是流化床化学反应器中的摩擦增压。在这种反应器中，气体以如此高的速率流过颗粒床，颗粒变得“流化”，颗粒和气体表现为流体混合物。该项目旨在了解摩擦充电如何影响气-颗粒悬浮液的流体动力学。将开发模型来解释和预测摩擦充电动力学和气-颗粒悬浮液的流体动力学如何受到材料特性、湿度和颗粒大小的影响。这项研究将是第一个专门研究摩擦充电和流化流体力学之间耦合的研究。该研究结果将广泛应用于涉及气固悬浮液的工业过程，因为摩擦充电会产生重大危害并降低工艺效率。该项目将为不同学术水平的学生提供参与研究的机会，包括参加普林斯顿大学暑期实验室学习计划的高中生。该项目的目标是开发和验证一个计算模型，该模型可以解释流体-颗粒流系统中的摩擦电荷和静电力，了解静电如何影响流体动力学，并了解这些系统中的瞬时充电速率。该模型将使用摩擦电荷的有效功函数来捕获由于接触颗粒的材料差异、接触颗粒的总电荷差异、接触颗粒的大小差异和湿度差异而引起的电荷转移。有效功函数将被合并到一个模型中，该模型结合了用于解决颗粒接触的离散元方法和用于解决更大尺度流动的计算流体动力学。模型参数将使用振动床实验进行校准。然后，模型的流化床动力学预测将通过实验进行测试，其中颗粒材料，尺寸，湿度和流化床壁面材料是系统变化的。研究结果将为工业从业者提供有用的信息，以改进涉及颗粒材料的工艺。