Investigating bubble dynamics on silicon carbide surfaces during flow boiling

Abstract

Silicon carbide (SiC) is a promising candidate for Accident-Tolerant Fuels (ATFs) in nuclear power plants, critical for maintaining functionality and extending service lifespan due to its superior heat transfer properties. However, the dynamics of bubble formation, size, and distribution on SiC surfaces during flow boiling, especially under the influence of porosity, remain poorly understood. This study aims to elucidate the impact of heat transfer characteristics and bubble distribution properties under flow boiling condition on SiC surface. An experimental was conducted with superheat ranging from 0 to 30K, subcooling ranging from 0 to 12K, and a maximum Reynolds number of 10,400. Videos were recorded and U-net was employed to identify bubble diameters, perimeters, orientations, and positions. Results indicate that the superheat significantly affects bubble size parameters, such as departure diameter and perimeter, but does not influence the distribution categories. Regarding bubble distribution, the aspect ratio and size of bubbles follow a log-normal distribution, while their orientation follows a normal distribution. Under the same experimental conditions, surfaces with higher porosities exhibit increased heat flux, and the Sauter mean diameter of bubbles is larger.

Keywords

• Sauter mean diameter
• Bubble distribution
• SiC surface
• Porosity
• Subcooled boiling