An experimental study on the heat transfer performance and pressure drop of TiO2-water nanofluids flowing under a turbulent flow regime

The influence of multi-walled carbon nanotubes on single-phase heat transfer and pressure drop characteristics in the transitional flow regime of smooth tubes

“…A possible reason for the increase in heat transfer is that the nanoparticles presented in the base liquid increase the thermal conductivity, delay and disturb the thermal boundary layer and accelerate the energy exchange process in the fluid due to the chaotic movement of the nanoparticles [13,17,39]. The increase in the thermal conductivity leads to an increase in heat transfer performance whereas the increase in viscosity leads to an increase in boundary layer thickness, which results in a decrease in heat transfer performance [40].…”

“…Duangthongsuk and Wongwises [17] tested TiO 2 -water nanofluids for the turbulent flow range. At a volume concentration of 1%, the heat transfer enhancement was approximately 26% whereas at a volume concentration of 2%, the heat transfer enhancement was reduced by 14%.…”

“…At a volume concentration of 18.9%, the heat transfer enhancement was approximately 50% for a Reynolds number greater than 1 000. Evaluating the literature shows that there are few works [6,7,8,9,10,11,13,14,17,18] that have reported on convective heat transfer characteristics of nanofluids, especially CNT nanofluids [3,12,15,16]. All of the studies considered in literature either test in the laminar [3,7,8,9,10,11,12,13,14,15] or high turbulent flow range [6,7,13,15,16,17] and very few tested in the transitional flow range [19].…”

Experimental study of turbulent forced convection of nanofluid in channels with cylindrical and spherical hollows

“…No effect of particle size on heat transfer was found in this work. Duangthongsuk and Wongwises [24] obtained 32% improvement of heat transfer at concentration of nanoparticles equal to just 1%, and 14% decrease in heat transfer coefficient at concentration of nanoparticles equal to 2% as compared to the base fluid.…”

“…Experiments on laminar and turbulent forced convection of water-based nanofluids have shown that nanofluids can improve the heat transfer coefficient within the range from a few percent up to 350% for carbon nanotubes [14][15][16][17][18][19][20][21][22][23][24][25]. A huge number of works appeared in this area over the last two decades.…”