Numerical study of macroscopic thermal diodes: Influence of interface topography and contact resistance

Macroscopic conductive solid-state thermal diodes, composed of two dissimilar materials, are approaching limits in rectification performance and operating range. Beyond material choice, alternative design strategies have been explored. This study numerically investigates two passive mechanisms affecting macroscopic solid-state thermal diodes: interface topographies between materials and thermal contact resistance at the interface. Results reveal key insights. First, while interface topographies have little effect on the rectification factor when contact resistance is negligible, they can extend the temperature range of rectification by up to 10 K. Second, a constant thermal contact resistance generally reduces rectification, but introducing temperature-dependent contact resistance at low temperatures can significantly enhance it. In one case, rectification improved from nearly zero to nearly unity. These findings provide guidelines for further research and optimization of solid-state thermal diodes for practical thermal management applications.