Measurement of the thermal conductivity of a water-based single-wall carbon nanotube colloidal suspension with a modified 3- ω method

Abstract

A modified 3-omega method applied to a suspended platinum microwire was employed to measure the thermal conductivity and convective heat transfer coefficient of a water-based single-walled carbon nanotube (CNT) solution (metallic single-wall nanotubes with 1.33 nm diameter and 1.14 wt% concentration), and an expression for calculating the convective heat transfer coefficient in such a free convective fluid was introduced. The measurement technique was validated for three model systems including vacuum, air and deionized water. It is found that there is excellent agreement between these three model systems with theoretical predictions. In addition, the frequency dependence on the third harmonic response measured in deionized water reveals the existence of a very low working frequency below 60 mHz. The thermal conductivity and convective heat transfer coefficient of the nanofluid (water-based single-wall CNT solution) were determined to be 0.73 +/- 0.013 W m(-1) K(-1) and 14 900 +/- 260 W m(-2) K(-1), respectively, which correspond to an enhancement of 19.4% in thermal conductivity and 18.9% in convective heat transfer as compared to water.

Experimental and theoretical studies of nanofluid thermal conductivity enhancement: a review

“…The most common techniques for measuring the thermal conductivity of nanofluids are the transient hot-wire method [9,12-15], temperature oscillation method [16,17], and 3-ω method [18,19]. As an example of a non-intrusive (optical) technique, forced Rayleigh scattering is discussed as well.…”

“…Alternative static experimental methods include the temperature oscillation method [16,17,28], micro-hot-strip method [29], steady-state cut-bar method [30], 3-ω method [18,31,32], radial heat-flow method [33], photo-thermal radiometry method [34], and thermal comparator method [19,35]. …”

Enhancing surface heat transfer by carbon nanofins: towards an alternative to nanofluids?

“…Clearly, there are difficulties in the experimental measurements [11], but the previous results also reveal some underlaying technological problems. First of all, the CNTs show some bundling or the formation of aggregates originating from the fabrication step.…”

Ionic liquid-based stable nanofluids containing gold nanoparticles

“…However, the anomalous enhancements of TC were only obtained in carbon nanotube-or metal-based nanofluids with low volume concentrations (vol.%) [11][12][13][14]. Then it is not difficult to understand why these nanofluids have recently been the focus of scientific research [18][19][20].…”