The growth of a vapor bubble in a superheated liquid is controlled by three factors: the inertia of the liquid, the surface tension, and the vapor pressure. As the bubble grows, evaporation takes place at the bubble boundary, and the temperature and vapor pressure in the bubble are thereby decreased. The heat inflow requirement of evaporation, however, depends on the rate of bubble growth, so that the dynamic problem is linked with a heat diffusion problem. Since the heat diffusion problem has been solved, a quantitative formulation of the dynamic problem can be given. A solution for the radius of the vapor bubble as a function of time is obtained which is valid for sufficiently large radius. This asymptotic solution covers the range of physical interest since the radius at which it becomes valid is near the lower limit of experimental observation. It shows the strong effect of heat diffusion on the rate of bubble growth. Comparison of the predicted radius‐time behavior is made with experimental observations in superheated water, and very good agreement is found.

The growth of vapor bubbles in superheated liquids. report no. 26-6

▪ Abstract This review examines recent advances made in predicting boiling heat fluxes, including some key results from the past. The topics covered are nucleate boiling, maximum heat flux, transition boiling, and film boiling. The review focuses on pool boiling of pure liquids, but flow boiling is also discussed briefly.

Boiling heat transfer

In this study, a complete numerical simulation of a growing and departing bubble on a horizontal surface has been performed. A finite difference scheme is used to solve the equations governing conservation of mass, momentum, and energy in the vapor-liquid layers. The vapor-liquid interface is captured by a level set method which is modified to include the influence of phase change at the liquid-vapor interphase. The disjoining pressure effect is included in the numerical analysis to account for heat transfer through the liquid microlayer. From the numerical simulation, the location where the vapor-liquid interface contacts the wall is observed to expand and then retract as the bubble grows and departs. The effect of static contact angle and wall superheat on bubble dynamics has been quantified. The bubble growth predicted from numerical analysis has been found to compare well with the experimental data reported in the literature and that obtained in this work

Dynamics and Heat Transfer Associated With a Single Bubble During Nucleate Boiling on a Horizontal Surface

Enhancing the critical heat flux (CHF) of industrial boilers by surface texturing can lead to substantial energy savings and global reduction in greenhouse gas emissions, but fundamentally this phenomenon is not well understood Prior studies on boiling crisis indicate that CHF monotonically increases with increasing texture density Here we report on the existence of maxima in CHF enhancement at intermediate texture density using measurements on parametrically designed plain and nano-textured micropillar surfaces Using high-speed optical and infrared imaging, we study the dynamics of dry spot heating and rewetting phenomena and reveal that the dry spot heating timescale is of the same order as that of the gravity and liquid imbibition-induced dry spot rewetting timescale Based on these insights, we develop a coupled thermal-hydraulic model that relates CHF enhancement to rewetting of a hot dry spot on the boiling surface, thereby revealing the mechanism governing the hitherto unknown CHF enhancement maxima

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M.G. Cooper

Papers

The microlayer in nucleate pool boiling

The microlayer and bubble growth in nucleate pool boiling

A general expression for the rate of evaporation of a layer of liquid on a solid body

A note on electrolytic analogue experiments for thermal contact resistance