Droplet boiling on heated surfaces with various wettabilities

Delayed Leidenfrost Effect of a Cutting Droplet on a Microgrooved Tool Surface

“…The increase of cutting fluid ratio, the decrease of contact angle θ (Figure S5) of the droplet on the microgrooved surface, and the increase of surface tension σ lv directly leads to the increase of capillary pressure P cap and wettability pressure P w , which finally leads to the increase of Leidenfrost point. Many scholars ,, have studied the effect of wettability on the Leidenfrost point, and the results show that the smaller the contact angle between the droplet and the wall, the stronger the hydrophilicity and the greater the increase in the Leidenfrost point. The main reason is attributed to the droplet bouncing due to the upward thermally induced momentum from the superheated surface.…”

“…More recently, Cao and Chen found a substantial increase in T DL on the trapezoidal fluted surface compared to the original smooth surface, suggesting that the vapor flow along the microgrooved surface resulted in an increase in T DL . Numerous studies have examined the impact regimes and spreading dynamics of droplets impacting heated surfaces in addition to the alteration of the Leidenfrost point under varied rough surfaces. − For example, Ma and his co-workers identified four boiling regimes of individual droplets, including nucleate boiling, nucleate boiling with violent atomization, transition boiling, and film boiling. Bertola divided the droplet regimes into three independent regimes and two mixed regimes; the independent regimes include secondary atomization, rebound, and splashing, and the mixed regimes are rebound with secondary atomization and splash with secondary atomization.…”

Droplet Boiling on Micro-Pillar Array Surface ─ Transition Boiling Regime

“…The single curve of the dimensionless maximum spreading factor versus the Weber number regarding water, ethanol, and FC-72 suggested the universality of the spreading dynamics in the film boiling regime regardless of liquid properties. − Guo et al reported a kind of microgrooved surface tool by laser ablation, which could obviously increase both the static and dynamic Leidenfrost points of the cutting fluid by adjusting the surface roughness. Ma et al experimentally observed that the nucleate boiling with a violent atomization regime and the transition boiling regime were absent on superhydrophobic surfaces. According to Kim et al, the failure to establish a stable vapor film resulted in a rise in the Leidenfrost temperature because heterogeneous bubble nucleation occurred in the nanoporous structures on superhydrophilic surfaces.…”

Enhancing Boiling Heat Transfer on a Superheated Surface by Surfactant-Laden Droplets

“…That is to say, a specific surfactant concentration can widen the effective heat-transfer temperature range of water. The possible reason is that the enhancements of wetting capacity and boiling heat transfer capacity of surfactant droplet are not synchronized with the change of concentration. ,, Accordingly, we define a new dimensionless number ( D ) by comparing the wetting power and boiling heat flux of water droplets to describe the changing trend of its LFP temperature with the surfactant concentration, which fits the experimental results of five surfactants accurately.…”