Article ID Journal Published Year Pages File Type
238464 Powder Technology 2010 4 Pages PDF
Abstract

Stable ethylene glycol based copper nanofluids were prepared through a two-step method, using polyvinyl pyrrolidone as dispersant, which was vital for the long-term stability of nanofluids. The substantial thermal conductivity enhancements were seen for the obtained nanofluids. For ethylene glycol based copper nanofluids with 0.5 vol.% at 50 °C, the enhancement ratio was up to 46%. The thermal conductivities depended strongly on the temperature of fluid, and the enhancement ratios increased along with the increasing temperatures. Brownian motions of Cu nanoparticles would play the key role on determining the effects of the temperature on thermal conductivity enhancement of nanofluids. The measured apparent thermal conductivity showed the time-dependent characteristic within 15 min. It indicated that the measurement should be made after 15 min at least to obtain the true thermal conductivities of ethylene glycol based copper nanofluids.

Graphical abstractStable ethylene glycol based copper nanofluids were prepared through a two-step method, using polyvinyl pyrrolidone as dispersant, which was vital for the long-term stability of nanofluids. The substantial thermal conductivity enhancements were seen for the obtained nanofluids. For ethylene glycol based copper nanofluids with 0.5 vol.% at 50 °C, the enhancement ratio was up to 46%. The thermal conductivities depended strongly on the temperature of fluid, and the enhancement ratios increased along with the increasing temperatures. Brownian motions of Cu nanoparticles would play the key role on determining the effects of the temperature on thermal conductivity enhancement of nanofluids. The measured apparent thermal conductivity showed the time-dependent characteristic within 15 min. It indicated that the measurement should be made after 15 min at least to obtain the true thermal conductivities of ethylene glycol based copper nanofluids.Figure optionsDownload full-size imageDownload as PowerPoint slideThermal conductivity enhancement ratios as a function of temperature

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Physical Sciences and Engineering Chemical Engineering Chemical Engineering (General)
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