▎ 摘　　要

Based on experiments, the flow and heat transport characteristics of two low-dimensional carbon nanofluids composed of multi-walled carbon nanotubes (MWNT) and graphene nanoplatelet (GNP) in micro-cylinder-groups are studied. The effective conductivities of the nanofluids were measured by a 3 omega method and the viscosity was determined by a rheometer. The measured viscosity is more susceptible to temperature and weight concentration than the thermal conductivity. The pressure drops, friction coefficient and Nusselt number of the nanofluids are further obtained. Serving as the origin of the spatial distribution of MWNTs and GNPs concentrations, the Soret effect on flow and heat transport justifies the thermally driven influence. As the Reynolds number increases, the friction coefficient decreases, and the Nusselt number increases. The increasing heating power had a negative effect on heat transfer performance of MWNT and GNP nanofluids, which was expressed by Soret effect. Compared to pure water, the heat transfer enhancement of GNP nanofluids is almost twice that of pure water while no significant heat transfer enhancement was observed for MWNT nanofluids. Besides, compared to the quasi-one-dimensional MWNTs, due to the unique two-dimensional structure of GNP nanoparticles, the GNPs serve as baffle plates in GNP nanofluids, resulting in significantly augmented friction coefficient and further leads to the enhancement of 200% in heat transfer. Compared to MWNT and previously reported SiC nanofluids in micro-cylinder-groups, GNP nanofluid serves as a good candidate for the heat transfer enhancement.