Direct numerical simulations of subcooled pool boiling: Studies of heat transfer and bubble dynamics

Pool boiling occurs in numerous applications, including the space industry, nuclear reactors, and thermal packaging. Liquid subcooling is defined as the difference between the saturation temperature and the bulk liquid temperature, which is known to affect heat transfer in certain thermal regimes because of its impact on the formation, growth, and dynamics of vapor bubbles. However, the precise nature and magnitude of its effects on the primary characteristics of nucleate boiling are currently not fully understood. Moreover, the available data in the literature currently indicate divergent trends. This work utilizes phase-resolving direct numerical simulations to elucidate the effects of subcooling in pool boiling in an attempt to shed light on the current uncertainty in the literature. We conducted a series of simulations where the bulk liquid temperature was varied, while the wall temperature and saturation temperature were kept constant. Bubble formation and departure, as well as their properties, such as equivalent bubble diameter, centroid coordinates, surface area, and bubble volume, were estimated for all computations. Our results demonstrate that the bulk liquid temperature affects the heat flux curve as well as bubble dynamics, while the latter exhibits a non-monotonic behavior.