On the solenoidal heat-flux in quasi-ballistic thermal conduction

Abstract

The Boltzmann transport equation for phonons is recast directly in terms of the heat-flux by means of iteration followed by truncation at the second order in the spherical harmonic expansion of the distribution function. This procedure displays the heat-flux in an explicitly coordinate-invariant form, and leads to a natural decomposition into two components, namely the solenoidal component in addition to the usual irrotational component. The solenoidal heat-flux is explicitly shown to arise by applying the heat-flux equation to a right-circular cylinder. These findings are important in the context of phonon resonators that utilize the strong quasi-ballistic thermal transport reported recently in silicon membranes at room temperature.

References in corpus (3)

• Direct Measurement of Room Temperature Non-diffusive Thermal Transport Over Micron Distances in a Silicon Membrane
• Superdiffusive heat conduction in semiconductor alloys -- I. Theoretical foundations
• A compact heat transfer model based on an enhanced Fourier law for analysis of frequency-domain thermoreflectance experiments

Cited by in corpus (3)

• Reduction of the effective thermal conductivity by circulation of the quasi-ballistic heat-flux
• A generalized enhanced Fourier law and underlying connections to major frameworks for quasi-ballistic phonon transport
• A compact heat transfer model based on an enhanced Fourier law for analysis of frequency-domain thermoreflectance experiments