Eur. Phys. J. Plus (2015) 130: 239
https://doi.org/10.1140/epjp/i2015-15239-5

Regular Article

Thermal conductivity of silica nanoparticle powder: Measurement and theoretical analysis

¹ School of Electric Power Engineering, China University of Mining and Technology, 221116, Xuzhou, People’s Republic of China
² School of Mechanical Engineering, University of Science and Technology Beijing, 100083, Beijing, People’s Republic of China
³ School of Materials Science and Engineering, University of Science and Technology Beijing, 100083, Beijing, People’s Republic of China

^* e-mail: huang198564@gmail.com

Received: 14 October 2014
Accepted: 18 October 2015
Published online: 4 December 2015

Abstract

The hot-wire method was applied to experimentally determine the thermal conductivity (TC) of a silica nanoparticle powder. A fitting model was further employed to analyze the experimental results and to predict the TC over a wider porosity scale. Results show that the effective TC of the silica-nanoparticle powder can be less than that of free air because of the low TC of both the silica nanoparticles and the air confined in the pore spaces; the relative contribution of the nanoparticle TC, the confined air TC, and the radiation heat transfer coefficient to the effective TC will significantly affect at which porosity the extreme value of the effective TC occurs; the porosity obtained when the contribution to the effective TC of the confined air equals that of the nanoparticles is the most favorable for constructing thermal insulation materials.