Revisiting the modelling of droplets passing through a superhydrophobic orifice

Berce, Jure (avtor), Jereb, Samo (avtor), Golobič, Iztok (avtor)

Precise analytical modeling of droplet size passing through a superhydrophobic orifice is vital for various industrial and scientific applications. The very few published theoretical models rely on spherical droplet assumptions, which proved inaccurate for larger orifices due to gravity-induced droplet deformation. To address this limitation, an analytical model for quasi-static droplet size separation is presented, successfully integrating contact angle hysteresis and gravitational effects. The new model determines the critical separation diameter by analyzing the free-surface droplet profile governed by surface tension, internal liquid pressure, and hydrostatic forces across a toroidal orifice edge. Validation using existing experimental results demonstrated excellent model accuracy (R$^{2}$ = 0.9815, RMSE = 0.0566 mm) and a detailed description of droplet shape evolution. A comprehensive parametric study subsequently revealed that contact angle hysteresis and orifice height have minimal practical influence on the critical droplet volume. Conversely, varying liquid properties significantly affect the separation size. Specifically, the critical droplet volume is mainly governed by the ratio of liquid density to surface tension, which dictates the extent of gravitational deformation. This framework provides a robust theoretical tool for designing passive, gravity-driven separation devices across diverse working liquids.

• Jezik: Angleški jezik
• Ključne besede: droplet separation, superhydrophobic surface, orifice, droplet size, force balance, laser-texturing, Young-Laplace equation
• Vrsta gradiva: Članek v reviji
• Tipologija: 1.01 - Izvirni znanstveni članek
• Organizacija: FS - Fakulteta za strojništvo
• Status publikacije: Objavljeno
• Različica publikacije: Objavljena publikacija
• Leto izida: 2026
• Št. strani: 15 str.
• Številčenje: Vol. 14, iss. 17, art. 2806
• PID: 20.500.12556/RUL-186416
• UDK: 532.21:544.722.132:621.9.048
• ISSN pri članku: 2227-9717
• DOI: 10.3390/pr14172806
• COBISS.SI-ID: 289577987
• Datum objave v RUL: 01.09.2026

Gradivo je del revije

• Naslov: Processes
• Skrajšan naslov: Processes
• Založnik: MDPI AG
• ISSN: 2227-9717
• COBISS.SI-ID: 523353113

Licence

• Licenca: CC BY 4.0, Creative Commons Priznanje avtorstva 4.0 Mednarodna
• Povezava: http://creativecommons.org/licenses/by/4.0/deed.sl
• Opis: To je standardna licenca Creative Commons, ki daje uporabnikom največ možnosti za nadaljnjo uporabo dela, pri čemer morajo navesti avtorja.

Sekundarni jezik

• Jezik: Slovenski jezik
• Ključne besede: separacija kapljic, superhidrofobne površine, reže, velikost kapljice, ravnovesje sil, lasersko teksturiranje, enačba Young-Laplace

Projekti

• Financer: ARIS - Javna agencija za znanstvenoraziskovalno in inovacijsko dejavnost Republike Slovenije
• Številka projekta: P2-0223
• Naslov: Prenos toplote in snovi

• Financer: ARIS - Javna agencija za znanstvenoraziskovalno in inovacijsko dejavnost Republike Slovenije
• Številka projekta: J2-50085
• Naslov: Raziskave medfaznih pojavov kapljic in mehurčkov na funkcionaliziranih površinah ob uporabi napredne diagnostike za razvoj okoljskih tehnologij prihodnosti in izboljšanega prenosa toplote (DroBFuSE)