SGER: Multiscale Modeling of Fluctuating Hydrodynamics with Energy Conservation

提案编号：CBET-0741359主要研究者： 乔、瑞所属： 克莱姆森大学提案标题：SGER：具有能量守恒的脉动流体动力学多尺度模拟颗粒悬浮液和聚合物流体中的热传递在许多工程系统中起着关键作用。虽然经典的流体动力学理论已经成功地描述了在这样的系统中的热传输时，颗粒尺寸是大的，它们可能变得不充分时，颗粒尺寸减小到纳米尺寸。特别是，热波动可能会显着影响在这样的系统中的热传输，因此，波动的流体动力学必须采用。然而，将热波动的非等温模拟在一个schemically自洽的方式是非常具有挑战性的，很少有有效的算法是可用的到目前为止，本项目的目标是开发一种新的多尺度模拟框架建模的波动流体动力学与能量守恒。在该框架下，分别采用分子动力学（MD）、能量守恒耗散粒子动力学（eDPD）和经典计算流体力学（CFD）方法模拟了原子、介观和宏观尺度下的热输运.在这样的框架下，纳米颗粒和流场的中尺度波动显式地模拟在一个显式的自洽方式。eDPD模型通过分子动力学模拟进行参数化，并且还可以通过直接耦合与经典流体动力学模拟相关联。我们将研究如何将原子细节纳入eDPD模型，以实现不同长度尺度的热传输建模的无缝集成。我们还将直接将物理化学相互作用引入eDPD模型，以更真实地描述颗粒相互作用。开发的代码将进行测试，通过比较模拟结果对选定的系统的实验结果。最后，我们将探讨接枝聚合物的微通道中的热输运建模。智力优点：所提出的多尺度建模技术将增加新的武器库的波动流体力学和复杂流体的建模。所提出的技术是有效的，因为消除了与移动边界的网格系统相关联的沉重的计算成本。该技术的粒子性质也使得复杂粒子形状的建模简单明了。新的建模框架提供的计算效率和灵活性，从而使一个广泛的类中尺度波动是重要的传输过程的有效建模。这将有助于阐明这些过程中的中尺度波动的影响，也将有助于为这些输送过程建立宏观模式。研究接枝聚合物通道中的传热，将有助于揭示通道中热涨落、聚合物构象和流体流动之间的相互作用，为优化此类系统中的传热奠定基础。更广泛的影响：该项目将为研究生提供一个机会，从事涉及计算物理、复杂流体和热科学的跨学科项目。新的多尺度框架开发将被记录在同行评价的专业期刊广泛传播。本计画所得之模拟结果将以图片及影片形式于网路上显示，以供教学之用。该网站将通过各种正式和非正式渠道向研究/教育专业人员，本科生/研究生和K-12学生做广告。基本概念的图形描述，例如，粒子的布朗运动，将有助于理解这些概念，并有助于激发学生对STEM学科教育的兴趣。研究成果还将开发成克莱姆森大学本科计算流体力学课程的教材。

Proposal Number: CBET-0741359Principal Investigator: Qiao, Rui Affiliation: Clemson UniversityProposal Title: SGER: Multiscale Modeling of Fluctuating Hydrodynamics with Energy ConservationThermal transport in particulate suspension and polymeric fluids plays a critical role in many engineering systems. While the classical hydrodynamic theories have been successful in describing thermal transport in such systems when the particulate size is large, they could become inadequate when the particulate size is reduced to nanometer dimension. Specifically, thermal fluctuation may significantly affect the thermal transport in such systems, and thus the fluctuating hydrodynamics must be adopted. However, incorporating thermal fluctuations into non-isothermal simulations in a thermodynamically self-consistent manner is extremely challenging and very few efficient algorithms are available so far.The objective of this project is to develop a novel multiscale simulation framework for modeling of fluctuating hydrodynamics with energy conservation. In the proposed framework, the thermal transport at atomistic, mesoscopic and macroscopic scales are modeled by molecular dynamics (MD), energy-conserving dissipative particle dynamics (eDPD) and classical computational fluid dynamics method, respectively. In such a framework, the mesoscale fluctuations of nanoparticulates and flow field are modeled explicitly in a thermodynamically self-consistent manner. The eDPD model is parameterized by molecular dynamics simulations and can also be linked to classical hydrodynamics simulation via direct coupling. We will investigate how to incorporate atomistic details into the eDPD model to achieve a seamless integration of modeling of thermal transport across disparate length scales. We will also introduce physicochemical interactions directly into the eDPD model for a more realistic description of particulate interactions. The developed codes will be tested by comparing the simulation results against available experimental results for selected systems. Finally, we will explore the modeling of thermal transport in microchannels grafted with polymers.Intellectual Merit: The proposed multiscale modeling technique will add new arsenal to the modeling of fluctuating hydrodynamics and complex fluids. The proposed technique is efficient as the heavy computational cost associated with meshing a system with moving boundaries is eliminated. The particle nature of the technique also renders the modeling of complex particle shape straightforward. The computational efficiency and flexibility provided by the new modeling framework will thus enable the efficient modeling of a broad class of transport processes in which mesoscale fluctuation is important. This will help to elucidate the effects of mesoscale fluctuations in these processes and will also help to develop macro-models for these transport processes. Study of the heat transfer in channels grafted with polymers will shed light on the interactions between thermal fluctuation, polymer conformation and fluid flow in the channel and lay the foundation for optimizing the heat transfer in such systems.Broader Impacts: The project will provide opportunity for a graduate student to work on an interdisciplinary project involving computational physics, complex fluids, and thermal sciences. The novel multiscale framework developed will be documented in peer evaluated professional journals for wide dissemination. Simulation results obtained in this project will be put into pictorial and movie formats and displayed on internet for teaching. The website will be advertised to research/education professionals, undergraduate/graduate student and K-12 students through various formal and informal channels. The graphic description of fundamental concepts, e.g., Brownian motion of particulates, will facilitate the understanding of these concepts and helps to ignite interest of students in pursuing education in STEM discipline. The research results will also be developed into the teaching materials for the undergraduate computational fluid dynamics course at Clemson University.