2024/07/24 by Aurélien Goerlinger, Goerlinger, Aurélien, Alice Germa +5
Agricultural and Biological Sciences · Engineering · #FOS: Physical sciences #Fluid Dynamics (physics.flu-dyn) #Fluid Dynamics and Heat Transfer #Particle Dynamics in Fluid Flows #Plant Surface Properties and Treatments
paper · pdf · doi:10.48550/arxiv.2407.17185
openalex publication_date 2024/07/24 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In this article, we experimentally investigate the impact of a submillimetric water jet on a horizontal surface heated well above the "static" Leidenfrost temperature of water. We observe the transition from a regime where a single drop grows at the impingement point to a regime of spray formation. The main control parameter appears to be the jet Weber number (\We). The first regime persists until \We \lesssim 30 whereas the spray formation occurs for \We \gtrsim 40. Surprisingly, we found no influence of the hot plate's temperature on the reported phenomena. We particularly focus on the second regime, where the liquid jet spreads on the plate, forming a liquid sheet that eventually lifts off and breaks into droplets. We characterized this regime by the radius rc of the liquid sheet when it is still in contact with the plate and the angle of ejection θ of the droplets. We further examine the ejected droplets by characterizing their speed and sizes. Simple models are proposed to predict the dependencies and order of magnitudes of rc and θ. We also aim to predict the critical Weber number at which the transition between the two regimes occurs. Our models show reasonable agreement with our experimental data. Finally, we compare the energy transferred from the jet to the droplets with results reported in the literature for impacts on unheated surfaces, finding a difference of nearly a factor 2.