Achieving thermal concentration based on fiber reinforced composite microstructures design

The ability to concentrate heat fluxes has recently attracted a great deal of interests due to its innumerable benefits in thermal management such as thermoelectricity, solar cells and other fields. In this work, we propose a practical design method of thermal concentration utilizing fiber reinforced composite microstructures. The effective thermal conductivity (ETC) of the microstructure is determined using effective medium theory, and the ETC is designed to meet the perfect conductivity profile calculated by the transformation thermodynamics approach. In the design, we choose microstructures with appropriate fiber volume fractions to match with the required conductivity distribution. Numerical examination is performed to verify the thermal concentrating effects. In the numerical model, we use stainless steel and air as the fiber material and matrix material, respectively. The proposed thermal concentrator can be easily fabricated by naturally available materials, which paves a new avenue for thermal harvesting in solar cells, thermal energy storage and other related fields. (paper)