Session: 08-02: Micro/Nanoscale Heat Conduction

Paper Number: 132048

132048 - Giftbte: An Efficient Deterministic Solver for Non-Gray Phonon Boltzmann Transport Equation 

Abstract: 

The advancements in nanotechnology have led to a significant demand for investigating thermal transport at the submicron scale. At this scale, the conventional heat diffusion equation based on Fourier's law is no longer applicable, and instead, the phonon Boltzmann transport equation (BTE) should be employed. Over the past two decades, substantial efforts have been dedicated to developing accurate and efficient numerical methods for solving the phonon BTE. These methodological advancements have greatly enhanced our understanding of thermal transport at the micro/nanoscale. Currently, it is crucial to develop open-source packages that can bridge the gap between methodological advancements and efficient tools in order to foster rapid progress in this field. However, the availability of open-source solvers for the phonon BTE is limited. Current packages are primarily based on methods with low accuracy or efficiency and are limited in predicting the effective thermal conductivity of several typical nanosturctures. There is still a lack of a general-purpose phonon BTE package with high accuracy and efficiency that can function like conventional computer-aided engineering (CAE) software.

This study introduces the GiftBTE, an open-source general-purpose software package for solving the phonon BTE. GiftBTE utilizes state-of-the-art deterministic solutions and offers both steady state and transient solvers. For the steady state solver, GiftBTE employs the implicit discrete ordinates method (DOM) with second-order spatial accuracy and the synthetic iterative scheme. For the transient solver, GiftBTE utilizes the explicit DOM with second-order spatial accuracy. These methodological advancements overcome statistical errors and achieve higher accuracy compared to packages that employ Monte Carlo methods, and also provide largely reduced requirements of the mesh number and fast convergence rate in the near-diffusive regime compared to previous packages. GiftBTE exhibits excellent computational efficiency, enabling realistic three-dimensional simulations of devices and material structures. By interfacing with first-principles calculations, this package allows for parameter-free and accurate computation of submicron thermal transport for arbitrary crystalline materials. By interfacing with external mesh generators, this package allows for the computation of arbitrary structures. The applications of GiftBTE include, but are not limited to, computing the effective thermal conductivity of various nanostructures, predicting temperature and heat flux fields in nanodevices, and simulating laser heating on materials involving small hot spots or ultra-fast processes.

The proposed open-source package presents remarkable capabilities in accurately and efficiently computing submicron thermal transport. It can also serve as a robust platform for conducting thorough investigations of thermal transport across various applications, rendering it invaluable to the communities of materials, electronics, energy, and heat transfer.

Presenting Author: Hua Bao Shanghai Jiao Tong University

Presenting Author Biography: Prof. Hua Bao is a professor at Global Institute of Future Technology in Shanghai Jiao Tong University. He received his B.S. in Department of Physics at Tsinghua University, China, in 2006, and obtained his Ph.D. from School of Mechanical Engineering at Purdue University in 2012. He joined Shanghai Jiao Tong University (University of Michigan-Shanghai Jiao Tong University Joint Institute) in 2012 as an assistant professor. He visited Purdue University in 2014 and Clemson University in 2016 as short-term visiting scholar. His research has been funded by many sponsors including National Science Foundation of China and Shanghai Municipal Science Foundation.

Authors: