NANOFLUIDS CONTAINING HYBRID SPHERE/CARBON NANOTUBE PARTICLES
Previous studies on nanofluids have focused on spherical or long-fiber particles. In this work, a new type of complex nanoparticles–hybrid sphere/carbon nanotube(CNT) particle, consisting of numerous CNTs attached to an alumina/iron oxide sphere–is proposed for applications in nanofluids. In such hybrid nanoparticles, heat is expected to transport rapidly from one CNT to another through the center sphere and thus leading to less thermal-contact-resistance between CNTs when compared to simple CNTs dispersed in fluids. CNTs have an extremely high thermal conductivity, but thermal resistance between the CNTs and the fluid has limited their performance in the nanofluids. The proposed hybrid sphere/CNT particles are synthesized by a spray pyrolysis followed by catalytic growth of CNTs. The spheres are about 70 nm in diameter in average, and the attached CNTs have a length up to 2 μ m. These hybrid nanoparticles are dispersed to poly-alpha-olefin withsonication and a small amount of surfactants to form stable nanofluids. The thermal conductivity of the fluids has been measured by a 3 ω -wire method over a temperature range 10 - 90 o C. The results indicate that the effective thermal conductivity of the fluids is increased by about 21％ at room temperature for particle volume fractions of 0.2％.
Zenghu Han Bao Yang S. H. Kim M. R. Zachariah
Department of Mechanical Engineering University of Maryland College Park, MD 20742 M. R. Zachariah Department of Mechanical Engineering University of Maryland College Park, MD 20742
国际会议
海南三亚
英文
2007-01-10（万方平台首次上网日期，不代表论文的发表时间）