Semi-implicit Lax-Wendroff kinetic scheme for multi-scale phonon transport

TL;DR

This paper introduces a semi-implicit Lax-Wendroff kinetic scheme for efficiently solving the phonon Boltzmann transport equation, enabling accurate multi-scale heat transfer predictions in microelectronics.

Contribution

A novel semi-implicit Lax-Wendroff scheme for the phonon BTE that is accurate across ballistic and diffusive regimes, overcoming limitations of relaxation time and mean free path.

Findings

Accurately predicts steady and unsteady heat conduction from ballistic to diffusive regimes.

Time and cell size are not limited by phonon relaxation time or mean free path.

Provides an efficient tool for multi-scale thermal management in microelectronics.

Abstract

Fast and accurate predictions of the spatiotemporal distributions of temperature are crucial to the multi-scale thermal management and safe operation of microelectronic devices. To realize it, an efficient semi-implicit Lax-Wendroff kinetic scheme is developed for numerically solving the transient phonon Boltzmann transport equation (BTE) from the ballistic to diffusive regime. The phonon BTE at the cell center is discretized under the framework of finite volume method, where the trapezoidal and midpoint rules are used to deal with the temporal integration of phonon scattering and convection terms, respectively. For the reconstruction of the interfacial distribution function, the phonon BTE at the cell interface is discretized in the form of finite difference method and solved numerically, where second-order upwind and central scheme are used to deal with the spatial interpolation and gradient of interfacial distribution function, respectively. The macroscopic governing equations are invoked for the evolution of macroscopic fields at both the cell center and interface, where the macroscopic flux is obtained by taking the moment of the interfacial distribution function. Numerical results show that the present scheme could accurately predict the steady/unsteady heat conduction in solid materials from the ballistic to diffusive regime, and its time and cell size are not limited by the relaxation time and phonon mean free path. The present work could provide a useful tool for the efficient predictions of the macroscopic spatiotemporal distributions in the multi-scale thermal engineering.