Self-propelled bubble pump in a nucleate boiling regime

The strong expansion pressure of the bubbles in the nucleate boiling regime is attractive as the driving force of the self-propelled machines. In this study, we first propose a self-propelled bubble pump using a deformable film beam on a hot flat metal plate at a nucleate boiling temperature. Here, the film beam breaks the symmetry of the bubble expansion direction, and thus it provides a net flow. By setting four beams in a circular manner, we experimentally observed a net circular flow with the angular velocity of similar to 10 rad s(-1), which corresponds to the central flow velocity of similar to 5 cm s(-1).