主讲人：Ma Yanbao（美国加州大学）

题目：Mesoscale Modeling and Simulations of Flow & Heat Transfer

时间：2015-6-26（星期五）10:00~11:30

地点：皇冠新体育app学术报告厅（新9教三楼）

举办单位：皇冠新体育app

摘要：While macroscale flow and heat transfer can be described by continuum principles, and atomistic scale transport can be calculated by molecular dynamics simulations, there is a lack of well-established mesoscale simulation tools to bridge the continuum and atomistic descriptions. Mesoscale modeling and simulations of mass and energy transport will provide the opportunities for breakthroughs in nanotechnologies for many applications including thermal management, energy conversion, conservation, and storage. There are two parts in this talk. The first part will focus on mesoscale modeling and simulation of non-Fourier heat transfer in micro/nanosystems, and the second part will focus on mesoscale flow simulations using multibody dissipative particle dynamics (MDPD).

Part I: Recent advances in nanostructured thermoelectrics, nanoelectronics and optoelectronics create a demand for greater scientific understanding of heat transfer at nanoscale where ballistic phonon transport becomes significant. Due to a lack of experimental observations and high fidelity numerical models, nanoscale ballistic phonon transport is still not well understood. Mesoscale modeling and simulations of mass and energy transport will provide the opportunities for breakthroughs in nanotechnologies for many applications including thermal management, energy conversion, conservation, and storage. A hybrid phonon gas model is introduced to describe transient ballistic-diffusive phonon transport in dielectric materials. For the first time, benchmark cases of heat-pulse experiments in NaF at low temperatures in ballistic, ballistic-diffusive, and diffusive regions have been completely reconstructed in numerical simulations. Then, a two-parameter heat conduction (TPHC) model is introduced to replace Fourier’s law for nanothermometry, including including transient thermal grating (TTG), frequency-domain thermoreflectance (FDTR), and time-domain thermoreflectance (TDTR).

Part II: Dissipative particle dynamics (DPD) is a coarse-grain method that can be applied to study the micro-/nanoscale liquid-structure interaction. Using DPD method, microdroplets interaction with solid surface and microparticles are studied. The results of the manipulation of a microparticle in digital microfluidic system, and nanoscale water bridge between an AFM tip and a flat substrate will be reported.

简历：Dr. Ma obtained his Ph.D.in Fluid Mechanicsfrom University of California at Los Angeles in 2004. After receiving his Ph.D. degree in mechanical Engineering fromUCLA,he joined Micro Systems Lab of UCLA and worked on micro-fluidic systems for biological analysis and biomedical diagnosis. In 2009,he joined University of California at Merced as an assistant professor.His broad research interests revolve around non-Fourier heat transfer modeling, mesoscale flow simulations, thermal management,and sustainable energy & water technologies.