关键词: 蓄冷, CO₂水合物, 纳米粒子, 导热性能

Abstract:

The thermal conductivity of CO₂ hydrate was measured in this study. The effects of three kinds of nanoparticles, including Al₂O₃, Cu, and SiO₂, with different mass fractions (0.05%, 0.1%, and 0.15%) and different nanoparticle dimensions (10, 30, and 50 nm) on CO₂ hydrate thermal conductivity were investigated. The results show that CO₂ hydrate thermal conductivity increases with the increase of temperature, ranging from 0.553 to 0.5861 W·m^-1·K^-1 at -5-5℃. And the additive of dispersant SDBS has positive influence on thermal conductivity of CO₂ hydrate-nanoparticle system. With the same mass fraction and particle size, Cu nanoparticles show better effect to enhance CO₂ hydrate thermal conductivity than Al₂O₃ and SiO₂ nanoparticles. But considering the formation of CO₂ hydrate and the suspension stability of solution, Al₂O₃ is more suitable to be used as the promoter of thermal conductivity. The thermal conductivity of CO₂ hydrate increases with the decrease of particle size of the Al₂O₃ nanoparticles. The increase rate of thermal conductivity in 15 nm hydrate-nanoparticle system is 12.7% higher than that in 50 nm hydrate-nanoparticle system. In addition, the increase of CO₂ hydrate thermal conductivity is improved from 4.2% to 8.2% when the mass fraction of Al₂O₃ nanoparticles increases from 0.05% to 0.15%.

Key words: cool storage, CO₂ hydrate, nanoparticles, thermal conductivity