SGER: Multiscale Modeling of Fluctuating Hydrodynamics with Energy Conservation

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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.