Water boiling at low pressure: dynamics of growth and bursting of bubbles in a plate-type evaporator
Abstract
Water is a good candidate to be used as an eco-friendly refrigerant. However, its behaviour under subatmospheric pressure needs to be better understood to optimize the efficiency and sizing of compact evaporators. Previous studies conducted in a plate-type evaporator highlighted that after the bubbles burst, the formation and evaporation of a thin liquid film on the evaporator wall has a major contribution on heat transfer. This work thus aims to characterize the dynamics of vapour bubbles during nucleate boiling, and more specifically the projection height after the free surface breakup. Using previous high-speed visualizations, the bubbles' characteristics are computed thanks to an ad-hoc Python program. It is shown that the projection height is correlated with the growth velocity and the size of the bubble reached just before it bursts. The influence of relevant dimensionless numbers on the projection height is also studied to determine the underlying predominant forces.
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