An experimental study on the effect of ultrasonication on viscosity and heat transfer performance of multi-wall carbon nanotube-based aqueous nanofluids

Sonication-assisted dispersion of carbon nanotubes in aqueous solutions of the anionic surfactant SDBS: The role of sonication energy

“…The sonication time was therefore suggested as a parameter to identify the degree of CNT dispersion [7,11]. However, other researchers [11][12][13][14] observed that the dispersion degree of a given CNT suspension depended on the sonication energy, rather than the sonication time. The sonication energy (E, J/mL), which is defined using the following equation, was therefore used to identify the degree of CNT dispersion [13]:…”

“…These results indicated that an insufficient supply of sonication energy could lead to the insufficient dispersion of CNTs, and dispersed CNT particles that are not small enough [12,13], while excessive sonication energy would not be economical. In previous studies, the sonication energies (E) applied to disperse CNTs in surfactant solutions ranged from 320 to 50400 J/mL, with the sonication time (t) ranging from 5 to 120 min (Table 1) [11,12,[15][16][17][18][19][20]. It is therefore necessary to examine the role of the sonication energy in surfactant-assisted CNT dispersion, to facilitate the effective use of energy in the industrial applications of CNTs.…”

“…It is therefore necessary to examine the role of the sonication energy in surfactant-assisted CNT dispersion, to facilitate the effective use of energy in the industrial applications of CNTs. In particular, the influence of surfactant concentration, as well as the concentration, diameter, length, and surface functional groups of CNTs should be examined, because these factors can significantly affect the CNT dispersion [12,[21][22][23]. The optimal energy is defined here as the minimum sonication energy needed to obtain a saturated suspension of CNTs in the surfactant solution.…”

CFD assessment of the effect of nanoparticles on the heat transfer properties of acetone/ZnBr2 solution

“…% of CNT) nanofluid a heat transfer enhancement of 350%. Garg et al [8] and Lao and Liu [9] reported much lower local heat transfer coefficient enhancements for CNT nanofluids when they used a higher solid concentration.…”

“…Ding et al and Garg et al [7,8] explained the mechanism of improved heat transfer for carbon nano-tube (CNT) nanofluid by a three dimensional web of nanotubes with heat transferred within the nanotubes, which has a much higher thermal conductivity than the base fluid. Ding et al [7] reported for carbon nano-tube (CNT) and water (0.5 wt.…”