Numerical simulation on size effect of thermal conductivity of 2D SiO ₂ nanowire

Nano insulations have excellent insulating performance and find wide application in hypersonic vehicle thermal protection technologies. In this study a two dimensional computational model based upon phonon radiative transfer equation for phonon transport in the solid of nano insulations was established. The discrete ordinate method was used to solve the transport equation numerically. The size effects in the longitudinal and transverse conductivity were numerically simulated for a 2D silica nanowire. Results showed that obvious size effect in the conductivity exists in the 2D nanowire and the conductivity was mainly influenced by the wire diameter. For the nanowire with the diameter between 2-4nm considered, its thermal conductivity was 15% less than the bulk material. Results obtained in this study may be useful in recognizing the heat transfer mechanism in solids of nano insulations.