GOALI: Fluid Dynamics, Heat Transfer, and Crystal Growth in Solvothermal Reactors: Modeling, Scaling, and Validation

GOALI：溶剂热反应器中的流体动力学、传热和晶体生长：建模、缩放和验证

• 批准号: 1336700
• 负责人: Abhilash Chandy
• 金额: $ 35.98万
• 依托单位: University of Akron
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-08-01 至 2018-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1336700&HistoricalAwards=false
• 关键词: GOALI; Fluid; Dynamics; Heat; Transfer

CBET-1336700PI: Chandy This industry-university collaborative project will develop and experimentally validate a computational fluid dynamics (CFD)-based model for crystal growth in supercritical fluids, with the goal of: (i) creating an integrated predictive thermofluid-mass transfer methodological approach and tool for crystal growth modeling, and (ii) demonstrating and applying the tools to optimization of an ammonothermal process for growth of single crystal gallium nitride (GaN), laying the groundwork for scale up of prototype and small scale reactors to a bulk manufacturing process and capability. Three critical areas will be considered: crystal growth numerical model, apparatus scale-up, and reactor optimization for enhanced mass transport. While several CFD simulations of hydrothermal and ammonothermal crystal growth processes have been conducted in the past, they have involved restrictive, simplified assumptions, extremely crude crystal growth models, and have not been validated experimentally. Not only does this research propose to create a more realistic growth model, but most importantly it intends to validate it experimentally. Like in many hybrid numerical/experimental undertakings, the strategy will be to use the experimental work for providing added insight for modeling while at the same time looking at the numerical work to guide the experimental work. This approach will advance a multi-scale, multi-physics phenomena modeling whereby the crystal growth model will benefit from seamless integration of 3-D momentum, energy and mass transfer 3-D equations (rather than 2-D axisymmetric) applied to a free convection environment. This research will for the first time, offer: (a) an experimentally 3-D computational tool for solvothermal crystal growth accounting jointly for turbulence, heat transfer, mass etching and deposition in a realistic reactor architecture of crystal seeds and porous nutrient; (b)concomitant experimental validation of the integrated multiphysics code (c) use experimental work to establish valid rules for geometric and dynamic similitude scaling for flows and reactor design; and (d) establish an assignment map between the calculated Rayleigh numbers and the types of flow regimes experimentally observed in cylindrical geometries with axisymmetric lateral heating.Fundamentally, the integrated experimental and numerical research will make a significant contribution to the general understanding of thermally driven fluid mechanics interacting with porous media as well as the associated surface reaction chemistry. In particular the model will be applied to closed cylindrical enclosures with laterally axisymmetric heated walls. The study will enable substantial process development through optimization of flow, heat and mass transfer, confident scale-up of processes in large, capital-intensive reactors, lower cost of design and construction of ammonothermal process reactors. SORAA and possibly other new entrants will stand to benefit significantly from the availability of a validated predictive and design numerical tool. The experiments developed in this program will form the basis of fluid mechanics training workshops for students at various levels with the added potential of providing some useful insights into other applications related to free convection. The broader impact and outreach activities that are centered on the experiments and simulations are aimed at increasing graduate research in Engineering at University of Akron, through enhancement of research and education partnerships. The knowledge gained from this study are expected to impact diverse processes in supercritical fluids, including synthesis of nanoparticles, zeolites, and novel materials and pyrolysis of waste materials.

CBET-1336700 PI：Chandy这个产学合作项目将开发和实验验证基于计算流体动力学（CFD）的超临界流体晶体生长模型，目标是：（i）创建用于晶体生长建模的集成预测性热流体-质量传递方法学途径和工具，以及（ii）展示并应用所述工具来优化用于生长单晶氮化镓（GaN）的氨化工艺，为将原型和小规模反应堆扩大到批量制造工艺和能力奠定基础。 三个关键领域将被考虑：晶体生长的数值模型，设备放大，和反应器优化，以增强质量传输。 虽然在过去已经进行了几次水热和氨化物晶体生长过程的CFD模拟，但是它们涉及限制性的、简化的假设、极其粗糙的晶体生长模型，并且没有经过实验验证。 这项研究不仅提出了一个更现实的增长模型，但最重要的是，它打算验证它的实验。 与许多混合数值/实验项目一样，该策略将使用实验工作为建模提供更多的见解，同时查看数值工作以指导实验工作。 这种方法将推进多尺度、多物理现象建模，从而晶体生长模型将受益于应用于自由对流环境的3-D动量、能量和质量传递3-D方程（而不是2-D轴对称）的无缝集成。 这项研究将首次提供：（a）一个实验性的三维计算工具，用于溶剂热晶体生长，在一个由晶种和多孔营养物组成的真实反应器结构中，同时考虑湍流、传热、质量蚀刻和沉积;（B）综合多物理场代码的伴随实验验证（c）利用实验工作为流动和反应器设计建立有效的几何和动态相似标度规则;以及（d）在计算的瑞利数和在具有轴对称横向流动的圆柱形几何结构中实验观察到的流态类型之间建立一个分配图，加热。从根本上说，综合实验和数值研究将作出重大贡献的热驱动流体力学与多孔介质相互作用的一般理解，以及相关的表面反应化学。 特别是该模型将被应用到封闭的圆柱形外壳与横向轴对称加热壁。 该研究将通过优化流动、传热和传质、在大型资本密集型反应器中可靠地扩大工艺规模、降低氨法反应器的设计和建造成本，实现实质性的工艺开发。 SORAA和可能的其他新进入者将从有效的预测和设计数值工具的可用性中受益匪浅。 在这个程序中开发的实验将形成流体力学培训研讨会的基础上，为学生在不同的水平与提供一些有用的见解到其他应用程序相关的自由对流的附加潜力。以实验和模拟为中心的更广泛的影响和推广活动旨在通过加强研究和教育伙伴关系，增加阿克伦大学工程学的研究生研究。 从这项研究中获得的知识预计将影响超临界流体中的各种过程，包括纳米颗粒，沸石和新材料的合成以及废料的热解。