Manipulating thermal fields with inhomogeneous heat spreaders

TL;DR

This paper introduces novel inhomogeneous heat spreaders with funnel shapes, designed using transformation techniques, to achieve uniform thermal fields, validated through numerical simulations, advancing heat manipulation technologies.

Contribution

It presents a new class of inhomogeneous, anisotropic heat spreaders designed via transformation methods, with practical approximations using isotropic layers for effective heat control.

Findings

Designs achieve uniform thermal fields across surfaces.

Validated designs with and without contact resistance effects.

Proposed configurations are feasible with layered isotropic materials.

Abstract

We design a class of spatially inhomogeneous heat spreaders in the context of steady-state thermal conduction leading to spatially uniform thermal fields across a large convective surface. Each spreader has a funnel-shaped design, either in the form of a trapezoidal prism or truncated cone, and is forced by a thermal source at its base. We employ transformation-based techniques, commonly used to study metamaterials, to determine the require thermal conductivity for the spreaders. The obtained materials, although strongly anisotropic and inhomogeneous, can be accurately approximated by assembling isotropic, homogeneous layers, rendering them realisable. An alternative approach is then considered for the conical and trapezoidal spreaders by dividing them into two or three isotropic, homogeneous components respectively. We refer to these simple configurations as neutral layers. All designs are validated numerically both with and without the effects of thermal contact resistance between interfaces. Such novel designs pave the way for future materials that can manipulate and control the flow of heat, helping to solve traditional heat transfer problems such as controlling the temperature of an object and energy harvesting.