简介: |
报告的摘要：
Effective thermal conductivity of carbon nanotube suspensions
Due to their high intrinsic thermal conductivity and essentially 1D structure, carbon nanotubes have the potential to greatly increase the thermal conductivity of liquids and other matrixes to which they are added. There has been disagreement in the literature as to whether existing macroscopic theories adequately describe the effective thermal conductivity of these nanofluids. Initial experiments reported enormous, "anomalous" thermal-conductivity enhancements for liquid suspensions of carbon nanotubes. In this talk, we detail our experiments on the effective thermal conductivity of carbon-nanotube suspensions. Particle aspect ratio and agglomeration state are carefully varied and characterized in order to allow quantitative comparison to Nan's effective medium theory. We also describe our efforts to experimentally realize "smart" heat transfer fluids having enhanced, anisotropic, and actively controllable thermal conductivities. Two approaches to this are described: The magnetic field-induced chaining of ferromagnetic particles, as well as the electric-field-induced alignment and self-assembly of carbon nanotubes in liquid suspension. We also provide a brief overview of our work on the nanoscale hydrodynamics and macroscopic rheological consequences of externally induced alignment of suspended carbon nanotubes.
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