Bubble coalescence at constant wall temperatures during subcooled nucleate pool boiling

► Heat transfer during bubble coalescence for subcooled nucleate pool boiling. ► High speed photographs and high speed local heat transfer rate measurements. ► Heat transfer decreases during fast coalescence (<1 ms after nucleation). ► Bubble oscillations after coalescence increase the surface heat fluxes. ► Long periods without nucleation lead to nucleation and fast coalescence of bubbles.