Multiscale Simulations of Multiphase Flows

多相流的多尺度模拟

• 批准号: 1335913
• 负责人: Gretar Tryggvason
• 金额: $ 33.87万
• 依托单位: University of Notre Dame
• 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: 2013-09-01 至 2017-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1335913&HistoricalAwards=false
• 关键词: Multiscale; Simulations; Multiphase; Flows

1335913PI: TryggvasonDirect numerical simulations (DNS) have made significant contribution to our understanding of multiphase flows over the last two decades. As their use has increased, and increasingly complex systems are being examined, two major issues have emerged. The first is that in many situations small-scale features emerge that require excessive (and often unachievable) resolution. These features either emerge spontaneously as thin films or threads or due to the addition of new physics that takes place on time and length scales very different than those of the flow. The second issue is that the wealth of data generated by DNS now far outstrips what can be used in standard models for the average flow field. This project is aimed at addressing both issues through the following two objectives. (1) The use of embedded analytical description for accurate capture of topology changes in simulations of multiphase flows. The approach is based on the observation that many small-scale features (films, threads, boundary layers, etc.) have a relatively simple structure and can therefore be described relatively accurately by analytical or semi-analytical models that are evolved concurrently with the fully resolved larger-scale motion. In this project, earlier work of films and mass transfer will be extended to capture accurately the rupture of films and threads. (2) Explore the evolution of various advanced statistical ways to describe the topology of complex multiphase flows. Such quantities include the area concentration tensor, average surface tension effects, and others, yet to be determined. The goal is to establish how these quantities correlate with the structure of the flow, and to attempt to model their evolution. Particular attention will be focused on how these quantities change during topology changes, their influence on the overall evolution of the flow, and the importance of predicting rupture accurately. The numerical methods will be made available through an online repository, along with a thorough documentation of the methodology and the use of the codes.Multiphase flows are critical in energy conversion, material processing, chemical industry, atmospheric processes, and living systems. Incremental improvement in the efficiency of such processes translates into billions of dollars in savings and new discoveries have the potential to transform whole industries. Computational studies will bring about both incremental and transformative changes in the management of multiphase systems. Educational material aimed at lowering the barrier to entry for new researchers will be developed and undergraduate students will be exposed to the area through research projects.This project is partially funded by an CISE/ACI CIF21 Venture Fund for Software Reuse.

1335913PI：在过去的二十年里，TryggvaronDirect数值模拟(DNS)为我们理解多相流做出了重大贡献。随着它们的使用越来越多，人们正在研究越来越复杂的系统，出现了两个主要问题。首先，在许多情况下，会出现需要过高(而且往往无法实现)分辨率的小规模特征。这些特征要么自发地以薄膜或线的形式出现，要么是由于在时间和长度尺度上发生的新物理的增加，而这些新物理尺度与流动的时间和长度尺度非常不同。第二个问题是，域名系统产生的丰富数据现在远远超过了平均流场的标准模型所能使用的数据。该项目旨在通过以下两个目标解决这两个问题。(1)使用嵌入式解析描述准确捕捉多相流模拟中的拓扑变化。这种方法是基于对许多小尺度特征(薄膜、线、边界层等)的观察。具有相对简单的结构，因此可以通过与完全分辨的更大尺度运动同时发展的解析或半解析模型来相对准确地描述。在本项目中，将扩展薄膜和传质的早期工作，以准确地捕捉薄膜和丝线的断裂。(2)探索描述复杂多相流拓扑结构的各种先进统计方法的演变。这些量包括面积集中张量、平均表面张力效应和其他尚未确定的量。我们的目标是确定这些量如何与流动的结构相关，并试图对它们的演变进行建模。将特别关注这些量在拓扑变化过程中如何变化，它们对流动的整体演变的影响，以及准确预测破裂的重要性。数值方法将通过在线存储库提供，并提供方法和代码使用的完整文档。多相流在能源转换、材料加工、化工、大气过程和生命系统中至关重要。这些过程效率的逐步提高转化为数十亿美元的节省，新发现有可能改变整个行业。计算研究将给多相系统的管理带来增量和变革性的变化。将开发旨在降低新研究人员进入门槛的教育材料，本科生将通过研究项目接触到该领域。该项目的部分资金来自CEISE/ACI CIF21软件重用风险基金。