Experimental study on single droplet impinging on a heated and inclined wall at early impaction stage

Tian, Wenlong; Zhang, Huang; Liu, Qianfeng

doi:10.1016/j.anucene.2020.107697

Cited by 8 publications

(2 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…where ∆t = 0.2281 s, ∆l = 0.255 m, σ ∆l = 1 mm, and σ ∆t = 2.5 × 10 −4 s. Given that the droplet does not maintain a perfectly spherical shape throughout its descent, the diameter of the droplet is represented by its equivalent diameter, D e , where D h and D v are the horizontal and vertical diameters of the droplet, respectively [4]. In this experiment, pixel analysis was employed to measure the geometric characteristics of the droplets.…”

Section: ) Error Analysismentioning

confidence: 99%

“…Notably, the Leidenfrost temperature for n-heptane droplets escalates with increased surface porosity, whereas water droplets do not undergo film boiling on porous surfaces. In an effort to delve into the behavior of a single droplet impacting a heated inclined wall, Liu et al [4] devised an experimental setup to assess the primary reactions of a droplet post-wall impact, varying parameters such as the wall temperature (T w = 40~262 • C), droplet Weber number (W e = 0.66~589), droplet Reynolds number (R e = 189~14,046), and the wall's inclination angle (α = 0 • ~45.6 • ). The findings indicate that elevating the Weber and Reynolds numbers promotes droplet spread rather than contraction.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Impact of Ceramic Micropillar Array and Fiber Layer Composite Structure on Kinematic and Heat Transfer Characteristics of Single Droplet Impacting a Wall

Zhang,

et al. 2024

Micromachines

View full text Add to dashboard Cite

The well-known limitations of spray cooling on high-temperature solids at the Leidenfrost temperature point have been significantly improved by a composite structure of steel micropillar arrays and insulating thin films. However, the physical mechanism of a single droplet impact on the walls of high-temperature composite structures in spray cooling remains elusive. We have experimentally studied and quantified the kinematic and thermal transfer characteristics of a single droplet impacting high-temperature micropillar arrays with fiber membrane composite structures. In particular, micropillar arrays of ceramic materials of different shapes (rectangular and cylindrical) used in this study were made using the more flexible PμSL technique, for which precision reaches the micron level. The results show that the presence and different layouts (embedded or placed on top) of the fiber layer significantly affect the spreading coefficient and thermal transfer efficiency of the droplets after impact. In terms of kinematic characteristics, unrelated to the structure of micropillar arrays, compared to structures without film, the maximum spreading coefficient of droplets significantly increased by more than 40% (43% for rectangular, 46% for cylindrical) when the fiber film was placed on top, and increased by more than 20% (20% for rectangular, 33% for cylindrical) when the fiber film was embedded. In terms of thermal transfer characteristics, at a temperature of 200 °C, the presence of the fiber layer changed the wettability of the surface of the micropillar structure, leading to a certain extension of the total evaporation time of the droplets compared to the surface of the micropillar structure without film.

show abstract

Section: ) Error Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%