Factors affecting nanofluids behaviour: A review

Abstract

Nanotechnology applications have occupied a wide range in engineering applications and achieved distinctive performance due to their potential as a working fluid instead of conventional liquids due to their outstanding performance. Sustaining stable performance nanofluids for a longer time retaining their properties without clustering and nanoparticles aggregation in the base fluid represents a significant challenge that can influence nanofluid properties and thermal behaviour. This review highlights some important factors that influence the stability of nanofluids, such as the size, concentration ratio of nanoparticles, and the type of base fluid, in addition discussing the methods used to improve the stability of nanofluids, such as the effect of cluster formation of nanoparticles in the base fluid due to Brownian motion and the role of the surfactants in preventing or reducing the agglomeration of nanoparticles, zeta potential and pH in estimating nanofluids stability. The factors mentioned affect the thermophysical properties of nanoparticles in preparing nanofluids and enhance their performance. This review provides information which helps improve the wide range usability of nanofluids for preparing stable nanofluids with good thermophysical properties.

Halloysite Nanotube (HNT) Dispersion Stability in 10% Ethanol-Water Mixture and Water

“…4, the particle size of HNT in water was observed to be decreasing due to the increase of zeta potential of the dispersions caused by counterions not fully adhering to the HNT surface, preventing particle clustering [14]. Meanwhile, higher HNT concentrations in 10% EtOH resulted in bigger particles due to ethanol molecules adhering to the HNT surface, which causes interactions between particles [2,5,[15][16]. This can be represented in Fig.…”

“…The bigger particle size causes more instability than smaller particles since it is susceptible more to downward movement. The Brownian motion will keep the dispersion stable when gravitational forces are not present [1,13]. As shown in Fig.…”

“…432 size affects their distance within the continuous phase, as they have an adequate repulsion due to their high zeta potential value. Further increase in base concentration leads to a slow depression in the absolute zeta potential value due to increased ionic strength [15][16][17][18][19][20]. 8, the H2O-HNT and 10% EtOH-HNT dispersions have decreasing settling velocities due to the increased viscosities.…”

Analysis and Optimization of the Fuel Consumption of an Internal Combustion Vehicle by Minimizing the Parasitic Power in the Cooling System

“…A study on the potential of enhancing vehicle cooling systems using nanofluids was conducted in the literature [24][25][26]. The analysis focused on the behavior of these nanoparticles to increase efficiency.…”

“…The potential of introducing a phase change material (PCM) to equalize thermodynamic processes was explored. The introduction of PCM resulted in a better temperature balance, leading to improved engine efficiency [24].…”