Full-Field Modeling of Heat Transfer in Asteroid Regolith: 2. Effects of Porosity

Andrew J. Ryan, Daniel Pino Muñoz, Marc Bernacki, Marco Delbo, Naoya Sakatani, Jens Biele, Joshua P. Emery, Benjamin Rozitis

Research output: Contribution to journalArticlepeer-review

Abstract

The thermal conductivity of granular planetary regolith is strongly dependent on the porosity, or packing density, of the regolith particles. However, existing models for regolith thermal conductivity predict different dependencies on porosity. Here, we use a full-field model of planetary regolith to study the relationship between regolith radiative thermal conductivity, porosity, and the particle non-isothermality. The model approximates regolith as regular and random packings of spherical particles in a 3D finite element mesh framework. Our model results, which are in good agreement with previous numerical and experimental datasets, show that random packings have a consistently higher radiative thermal conductivity than ordered packings. From our random packing results, we present a new empirical model relating regolith thermal conductivity, porosity, temperature, particle size, and the thermal conductivity of individual particles. This model shows that regolith particle size predictions from thermal inertia are largely independent of assumptions of regolith porosity, except for when the non-isothermality effect is large, as is the case when the regolith is particularly coarse and/or is composed of low thermal conductivity material.

Original languageEnglish (US)
Article numbere2022JE007191
JournalJournal of Geophysical Research: Planets
Volume127
Issue number6
DOIs
StatePublished - Jun 2022

Keywords

  • airless bodies
  • numerical modeling
  • regolith
  • thermal conductivity
  • thermophysics

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

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