Water transportation using a low-height overhang structure along with an expansion pressure of bubbles in a nucleate boiling region

Abstract

Effective use of low-grade energy is a vital issue for a more sustainable society. Here, we propose a water pump using a low-height overhang structure that effectively uses an expansion pressure of bubbles in a nucleate boiling region. Specifically, by fabricating a periodic overhang structure on a brass surface, we show that a ∼20 mm/s net flow can be generated in a nucleate boiling regime. In addition, by observing bubbles with a high-speed camera of 960 fps, we find that bubbles are generated selectively in the overhang structure and grow to push out water in a lateral direction. Furthermore, by proposing a simple model that considers the expansion pressure of bubbles, we succeed in explaining the experimental results to some extent. Our findings should contribute to the effective use of low-grade energy in a nucleate boiling regime.