Pyroelectric effects inducing negative feedback boiling heat transfer

Abstract

Boiling is governed by bubble behaviors, and energetic bubble formation is favourable for boiling heat transfer efficiency but is prone to a boiling crisis. State-of-the-art boiling surfaces with active and passive modifications ensure a good compromise of a high heat transfer coefficient (HTC) and safety margin. However, bubble behaviors cannot be adjusted for two-phase boiling systems without in situ surface wettability control. Here we report a novel method to manipulate boiling via temperature-dependent wettability of pyroelectric coatings without any extra input. This wettability control is confirmed by the variation of hydrophilic hydroxyl radicals. As a result, we can achieve negative feedback boiling by reversibly altering the surface's wettability through alternate heating and cooling, retaining boiling in the high HTC region. Our work shows that pyroelectric coatings enhance the HTC at low heat fluxes and improve safety margins at high fluxes. The findings offer insights into improving heat transfer and highlight the potential of pyroelectric coatings for wettability control.