Boiling propagation of water on a smooth film heater surface

Boiling propagation of water is investigated experimentally at atmospheric pressure using a small platinum film heater having a surface smoothness of nanometer order. The test water is highly superheated up to approximately 140 K before the inception of boiling on the stepwise powered heater. Boiling is triggered at the prescribed wall superheat before spontaneous inception by generating a boiling bubble at a local section of the heater. The behavior of the propagating bubble is revealed by stroboscopic photography. The propagation takes place at wall superheats larger than approximately 50 K, and the propagation velocity increases significantly with wall superheat up to 24 m/s. The propagating front is followed by prompt collapse of the bubble at the tail, resulting in rapid migration of the boiling region. The measured propagation velocity is compared with the value predicted using an analytical model reported in the literature, and reasonable agreement is shown over the entire range of the wall superheat.