Calculation of heat transfer coefficients for explosive boiling of a liquid under conditions of low pressure

The paper discusses the problem of determining the temperature head for calculating the heat transfer coefficient during explosive boiling of a liquid on a smooth horizontal surface under conditions of low pressure. The task of the work is obtaining the method for determining the characteristic pressure for calculating the temperature of saturated vapors. As a result, it is found that the difference between the heat transfer coefficients calculated at the pressure specified at the beginning of the experiment and the pressure averaged over time differ on average by 5%.

Effect of the Hybrid Hydrophobic-Hydrophilic Nanostructured Surface on Explosive Boiling

The influence of different wettability on explosive boiling exhibits a significant distinction, where the hydrophobic surface is beneficial for bubble nucleation and the hydrophilic surface enhances the critical heat flux. Therefore, to receive a more suitable surface for the explosive boiling, in this paper a hybrid hydrophobic–hydrophilic nanostructured surface was built by the method of molecular dynamics simulation. The onset temperatures of explosive boiling with various coating thickness, pillar width, and film thicknesses were investigated. The simulation results show that the hybrid nanostructure can decrease the onset temperature compared to the pure hydrophilic surface. It is attributed to the effect of hydrophobic coating, which promotes the formation of bubbles and causes a quicker liquid film break. Furthermore, with the increase of the hydrophobic coating thickness, the onset temperature of explosive boiling decreases. This is because the process of heat transfer between the liquid film and the hybrid nanostructured surface is inevitably enhanced. In addition, the onset temperature of explosive boiling on the hybrid wetting surface decreases with the increase of pillar width and liquid film thickness.