Vol. 337 No. 1 (2026)

DOI https://doi.org/10.18799/24131830/2026/1/5462

Thermal and secondary splashing of water droplets on heat transfer surfaces

Relevance. In spray cooling systems of modern high-power devices, including processors and power electronics components, the roughness and wettability of heat transfer surfaces affect hydrodynamic droplet evaporation regimes. These regimes include deposition, rebound, thermal splashing, secondary splashing, and the Leidenfrost state and determine the maximum removable heat flux. The continuous increase in heat dissipation density pushes traditional cooling approaches to their limits. Development of next-generation heat transfer surfaces, including liquid-infused surfaces (LIS), represents a promising direction for improving heat removal efficiency. Analysis of near-surface temperature variation on aluminum–magnesium alloy surfaces, including polished and two types of LIS, confirms the fundamental role of wettability and reveals qualitative differences in parent droplet dispersion mechanisms depending on surface type. Aim. Evaluation of the cooling efficiency of liquid-infused heat transfer surfaces during evaporation of a single water droplet under various hydrodynamic regimes, including thermal and secondary splashing. Methods. Cooling efficiency was evaluated based on analysis of temperature variation in the near-surface layer during interaction between a water droplet and a heated surface. Experiments were conducted using a single 10 μl water droplet over a surface temperature range of 100–280°C. Results and conclusions. The authors have carried out a quantitative comparison of cooling efficiency between liquid-infused and polished surfaces. Distinct droplet dispersion mechanisms associated with thermal and secondary splashing were identified. Despite delayed Leidenfrost onset on liquid-infused surface, the latter exhibits the lowest cooling efficiency among those studied. At elevated temperatures, cooling efficiency of liquid-infused surfaces further decreases due to depletion of the lubricant layer, which degrades heat removal and limits their practical application in droplet cooling systems under prolonged or repeated thermal loads.

Keywords:

heat transfer surface, thermal splashing, secondary splashing, puffing, evaporation, laser texturing

Authors:

D.V. Feoktistov

D.M. Klepikov

D.O. Glushkov

References: