Monte Carlo Modeling of the Thermal Conductivity of Porous Cometary Ice

摘要: Abstract The basic structure of comet nuclei is an aggregation grains, with a size distribution that extends over several orders magnitude and similar pores. Although attempts have been made to assess the effect porosity on thermal conductivity, pore has ignored. Modeling porous wide would require very fine 3-D grid, so as accommodate smallest largest voids. In order circumvent this difficulty, we adopt hierarchical procedure. Thus assume random fractal use Monte Carlo model. configuration cube unit cells two types, (ice) filled void, randomly distributed. Their relative number corresponds prescribed porosity. We solve heat transport equation for until steady state obtained, from solution effective conductivity derived. calculations are repeated range porosities temperatures, since ice temperature dependent. serves cell in larger cube, way medium built up. find lowered by at high porosities. correction factor, obtained fit results our calculations, expressed smooth function porosity, which tends zero approaches percolation threshold solid. If only known, not uniquely determined, but rather values possible. Only if pores known does become determined.