Multiscale Modeling and Simulation of Evaporation and Boiling in Graded Micro- and Nanoporous Structures

PI：Zhang，YuwenCBET-1066917本研究的目标是通过多尺度建模、模拟和实验来研究孔径从10 nm到100微米的梯度微孔和纳米孔结构中的蒸发和沸腾。发展了一种混合分子动力学(MD)模型，该模型包括纳米粒子核心的连续介质模型和纳米粒子表面和工作流体中的分子的MD模型。气相中的输运现象将使用直接模拟蒙特卡罗(DSMC)来模拟。通过在MD和DSMC区之间的界面附近增加两个缓冲层来考虑这两个区之间的双向耦合。宏观连续介质模型中的耦合因子将通过模拟孔隙模型中不同相间的动量、热量和质量交换来获得。所提出的混合多尺度模式比现有的大尺度连续模式有了很大的进步。最先进的基本工艺模型将允许技术用户寻找优化的工艺策略，以提高各种两相设备的性能，如热管。所开发的多尺度模型还可以扩展到分析燃料电池多孔电极和气体分布层中的传输现象，以优化燃料电池的设计。该模拟模型还可以应用于生物和微纳尺度的换热。该软件将在热流体Central(https://www.thermalfluidscentral.org/e-resources/)的电子资源部分提供

PI: Zhang, YuwenCBET - 1066917 The objective of the proposed research is to investigate evaporation and boiling in graded micro- and nanoporous structures with pore sizes ranging from 10 nm to 100 microns by multiscale modeling and simulation and experiments. A hybrid molecular dynamics (MD) model that includes continuum model for the core of the nanoparticles and MD model for molecules of the nanoparticles at surface and working fluid will be developed. The transport phenomena in the vapor phase will be modeled using the Direct Simulation Monte Carlo (DSMC). The two-way coupling between the MD and DSMC regions are considered by adding two buffer layers near the interface between these two regions. The coupling factors in the macroscale continuum model will be obtained by modeling momentum, heat and mass exchanges between different phases in the pore-scale model. The proposed hybrid multiscale models represent significant advancements over the existing macroscale continuum models. The state-of-the-art fundamental process models will allow the users of the technologies to search for optimized processing strategies to improve the performance of various two phase devices such as heat pipes. The developed multiscale model can also be extended to analyze transport phenomena in porous electrodes and gas distribution layers of the fuel cells to optimize the design of fuel cells. The simulation model can also be applied to biological and micro- and nanoscale heat transfer. The software will be made available at the e-Resource section of the Thermal-Fluids Central(https://www.thermalfluidscentral.org/e-resources/)