Experimental studies on CHF characteristics of nano-fluids at pool boiling

The Effect of Micro/Nanoscale Structures on CHF Enhancement

“…They conducted experiments with varying flow velocities, starting from 0 m/s (effectively pool boiling) up to 4 m/s. A CHF enhancement of 50% was found at 0 m/s, consistent with the pool boiling reported by previous researchers [3][4][5]. After the boiling experiments, Ahn et al, [14,15] used a scanning electron microscope (SEM) to examine the heater surfaces, and they measured the contact angle.…”

“…The similarity between the CHF of nanoparticlefouled surfaces in pure water and that of a clean surface in nanofluids (Fig. 2) suggests that the CHF of nanofluids is related to the modification of surfaces immersed in the fluid [3,5,8].…”

“…The CHF has been shown to increase in pool-boiling nanofluid experiments using various concentrations of TiO2 or Al2O3 nanoparticles on Ni-Cr wire under atmospheric conditions [3,5,8]. Scanning electron microscopy (SEM) has revealed that nanoparticle coatings are generated on the wire surfaces during the pool boiling ( Fig.…”

“…Nanoparticle-fouled surfaces have significantly greater wettability than do bare surfaces, as can be determined by the reduction in the measured static contact angle of droplets [5]. This observation was based on a review of the prevalent CHF theories, which state that the improved wettability caused by the nanoparticle layer can be used to predict CHF enhancement.…”

Anomalous Increase in Specific Heat of Binary Molten Salt-Based Graphite Nanofluids for Thermal Energy Storage

“…This has been attributed to the change of the surface wettability due to nanoparticle deposition on heater surfaces. After the observation in these pool-boiling experiments, initially modified heater surfaces were employed to confirm the critical heat flux performance [7,8]. Significant enhancements in the critical heat flux were acquired from previous studies with the heater surface modified by nanomaterials [9][10][11][12].…”