Related Experiment Video
Updated: Jul 15, 2026
08:34
Visualization of High Speed Liquid Jet Impaction on a Moving Surface
Published on: April 17, 2015
11.4K
Droplets Impacting on Superheated Surfaces with Asymmetric Re-Entrant Microgrooves
Ting-Yu Hsu1, Hung-Chih Chen1, Chung-Te Huang1,2
1Department of Mechanical Engineering, National Taiwan University, Taipei, 10617, Taiwan.
Small Methods
|February 24, 2025
Summary
Engineered surfaces with asymmetric re-entrant microgrooves (ARG surfaces) significantly improve droplet cooling on hot surfaces. These novel surfaces reduce droplet contact time and enhance heat transfer, even at extreme temperatures up to 725°C.
Area of Science:
- Materials Science
- Thermal Engineering
- Fluid Dynamics
Background:
- Droplet impact on hot surfaces is vital for thermal management.
- Efficient cooling requires rapid droplet detachment, directional shedding, and suppressed Leidenfrost effect.
- Existing surfaces fail to achieve all these simultaneously at high temperatures.
Purpose of the Study:
- To introduce and characterize novel asymmetric re-entrant microgroove (ARG) surfaces.
- To demonstrate simultaneous reduction in contact time, directional shedding, and Leidenfrost suppression.
- To develop a theoretical model for predicting Leidenfrost points (LFPs) on these surfaces.
Main Methods:
- Fabrication of ARG surfaces with asymmetric re-entrant microgrooves.
- Experimental droplet impact analysis at temperatures from 350 to 650°C.
- Development of a theoretical model for LFP prediction.
- Comparative thermal performance analysis using temperature profiling.
Main Results:
- ARG surfaces exhibit LFPs as high as 725°C.
- Contact times were below the theoretical limit across tested temperatures.
- Enhanced droplet velocities and displacement factors were observed.
- ARG surfaces showed superior cooling performance compared to plain silicon surfaces.
Conclusions:
- ARG surfaces offer a promising solution for efficient cooling in high-temperature applications.
- These surfaces overcome limitations of existing engineered surfaces for droplet thermal management.
- The developed theoretical model aids in designing surfaces with tailored LFP characteristics.
Related Concept Videos
02:39Phase Transitions: Vaporization and Condensation
The physical form of a substance changes on changing its temperature. For example, raising the temperature of a liquid causes the liquid to vaporize (convert into vapor). The process is called vaporization—a surface phenomenon. Vaporization occurs when the thermal motion of the molecules overcome the intermolecular forces, and the molecules (at the surface) escape into the gaseous state. When a liquid vaporizes in a closed container, gas molecules cannot escape. As these gas phase molecules...
01:20Mechanisms of Heat Transfer II
In convection, thermal energy is carried by the large-scale flow of matter. Ocean currents and large-scale atmospheric circulation, which result from the buoyancy of warm air and water, transfer hot air from the tropics toward the poles and cold air from the poles toward the tropics. The Earth’s rotation interacts with those flows, causing the observed eastward flow of air in the temperate zones. Convection dominates heat transfer by air, and the amount of available space for the airflow...
01:16Precipitate Formation and Particle Size Control
In precipitation gravimetry, the precipitating agent should react specifically or selectively with the analyte. While a specific reagent reacts with the analyte alone, a selective reagent can react with a limited number of chemical species.
The obtained precipitate should be either a pure substance of known composition or easily converted to one by a simple process, such as ignition or drying. In addition, the precipitate should be insoluble and easily filterable. In general, filterability...
The obtained precipitate should be either a pure substance of known composition or easily converted to one by a simple process, such as ignition or drying. In addition, the precipitate should be insoluble and easily filterable. In general, filterability...
00:52Washing, Drying, and Ignition of Precipitates
After filtration, the precipitate is washed to remove coprecipitated impurities and any remaining mother liquor. Colloidal precipitates, such as silver chloride, are washed with an electrolyte (such as dilute nitric acid) to prevent the peptization of the precipitate. In the case of slightly soluble precipitates, the wash solution contains a common ion to reduce solubility. Lead sulfate, which is slightly soluble in water, is washed with dilute sulfuric acid. Similarly, wash solutions may be...