GOALI: ADVANCED STUDY OF MENISCUS-CONTROLLED MATERIALS PROCESSING

先进的无网格建模和实验研究的控制材料加工项目概述光伏/太阳能产业已经取得了超过20%的增长率在过去几年中，未来的增长预计将继续在25-30%或更高的年，由于世界范围内的能源短缺。目前，约85%的现有生产涉及晶体硅技术。增加使用光伏发电的最关键的障碍是硅片的高成本和用于制造光伏电池的成本有效的硅原料的限制。肖特太阳能公司使用的边缘限定薄膜生长（EFG）技术是一种高效的可控硅生长工艺，用于生产制造太阳能电池的硅片，而不会产生“切口损失”。为了进一步降低成本和提高产量，重要的是找到用于生长具有低应力和低碳化硅（SiC）颗粒掺入的薄管/带的最佳设计/条件。这个GOALI建议的主要研究目标是定量地了解弯月面动力学及其在各种配置下与凝固的相互作用，并发展新的理解外来粒子的形成和纳入在弯月面凝固过程。为了实现这些目标，研究任务包括开发一个先进的基于粒子的模型，使多尺度传输现象的有效建模。该模型将被用来研究弯月面动力学，颗粒形成，沉淀和合并。所得到的过程模型将用于模拟实验室和工业实验，以进行过程优化。实验室实验也将被设计和执行，以检查在各种机械/热扰动下的弯月面和管厚度的动态，并研究在凝固过程中的颗粒掺入的拉速和模头顶部温度的影响。实验数据也将被用来建立颗粒掺入和拉速/模头顶部温度之间的关系。与肖特太阳能公司合作，已经并将继续进行全尺寸实验，为模型验证提供实验数据。在过程建模和实验室实验的帮助下，工业增长系统可以重新设计，操作条件可以重新检查。智力上的优点。拟议的研究将显着推进弯月面的稳定性和动力学，颗粒沉淀和生长，多相流，并在凝固过程中的颗粒掺入的基本理解。所提出的基于两相粒子的模型是一种创新的工具，用于解决许多不同类型的自由表面流动和湍流控制的凝固问题，如钎焊，焊接，喷墨喷涂，液滴涂覆和复合材料制造。该模型也可以应用于复杂的多尺度输运现象。更广泛的影响。在过程建模、材料加工和制造领域培养工程专业学生对美国工业至关重要。该项目为大学和工业界提供了一个合作和互补彼此专业知识的机会。预计通过拟议的研究增强的理解将有助于工艺设计和优化，显着降低太阳能应用硅片的成本，这是迫切需要的可再生能源，以缓解能源短缺。该提案的成功将有可能增加光伏产业在世界能源领域的市场份额。

Advanced meshless modeling and experimental study of meniscus-controlled materials processingProject summaryPhotovoltaic/solar energy industry has achieved growth rates in excess of 20 % over the past several years and future growth is expected to continue at 25-30% or more annually due to worldwide energy shortage. Currently, about 85% of the current production involves crystalline silicon technology. The most critical barrier to the increased use of photovoltaic generated electricity is the high cost of silicon wafers and the limitation to cost-effective silicon feedstock used to manufacture the photovoltaic cells. The edge-defined film-fed growth (EFG) technique used at Schott Solar is an efficient meniscus-controlled growth process for producing silicon wafers that are made into solar cells without "kerf loss". To further reduce costs and improve yield, it is important to find the optimal design/conditions for the growth of thin tubes/ribbons with low stress and low silicon carbide (SiC) particle incorporation. The main research goals of this GOALI proposal are to quantitatively understand meniscus dynamics and its interaction with solidification under various configurations and to develop new understanding of foreigner particle formation and incorporation in meniscus-solidification processing. To achieve the goals, the research tasks include the development of an advanced particle based model to enable an efficient modeling of multiscale transport phenomena. The model will be used to study meniscus dynamics, particle formation, precipitation, and incorporation. The resultant process model will be used to simulate the laboratory and industrial experiments for process optimization. The laboratory experiments will also be designed and performed to examine the dynamics of meniscus and tube thickness under various mechanical/thermal perturbations and to study the effects of pull rate and die-top temperature on particle incorporation during solidification. The experimental data will also be used to establish the relationships between particle incorporation and pull rate/die-top temperature. Collaborated with Schott Solar, the full-scale experiments have been and will continue to be conducted to provide the experimental data for model validation. In the help of process modeling and laboratory experiments, industrial growth system can be redesigned and operating conditions can be reexamined. Intellectual merit. The proposed research will significantly advance the fundamental understanding of meniscus stability and dynamics, particle precipitation and growth, multiphase flow, and particle incorporation in solidification processing. The proposed two-phase particle-based model is an innovative tool for solving many different kinds of free surface flow and meniscus-controlled solidification problems, such as soldering, welding, inkjet painting, droplet coating, and composite materials manufacturing. This model can also be applied to complex multiscale transport phenomena. Broader impact. Training engineering students in the area of process modeling, materials processing and manufacturing is critical for US industry. This project provides an opportunity for university and industry to work together and complement each other's expertise. It is anticipated that the enhanced understanding through the proposed research will help process design and optimization, significantly reducing cost of silicon wafers for solar application, which is urgently needed as a renewable energy source to alleviate energy shortage. The success of this proposal will potentially increase market share of photovoltaic industry in the world energy sector.