Near-Field Heat Transfer Percolation in Nanoparticles based Composite Media

TL;DR

This paper investigates near-field radiative heat transfer in nanoparticle composites, revealing an early percolation threshold that significantly enhances thermal conductivity, with implications for experimental validation.

Contribution

It introduces a model showing near-field percolation occurs at much lower volume fractions than mechanical percolation, impacting thermal management strategies.

Findings

Near-field percolation occurs at a volume fraction of 0.033.

Thermal conductivity increases sharply at low nanoparticle concentrations.

Proposes an experimental method to detect near-field contact.

Abstract

Near-field radiative heat transfer is investigated in composite media including nanoparticles. By modeling pair interactions only, the effective thermal conductivity due to near field radiation is calculated based on a thermal nodes model. We highlight the onset of a Near-Field percolation occurring much earlier than the mechanical percolation at critical volume fraction f=0.033. This 15 mechanism drastically increases the thermal conductivity even at low volume fractions. It also indicates a simple experimental protocol to prove Near-Field contact.