Pool boiling enhancement through bubble induced convective liquid flow in feeder microchannels
Bubbles departing from the nucleation sites induce a liquid flow from the bulk to the heated surface during pool boiling. Alternating the nucleating regions with non nucleating regions facilitates separate liquid vapor pathways for departing vapor bubbles and returning liquid. We explored an additional enhancement through liquid feeder channels on the heater surface directing the returning liquid towards the nucleating region. The nucleating bubbles were confined to the nucleating region as the returning liquid flow induced strong convective currents over the non nucleating regions. In the best performing configuration, the nucleating regions were 0.5 mm wide, separated by non nucleating regions of width 2.125 mm, which corresponded to the bubble departure diameter. The non nucleating regions contained 0.5 mm wide feeder channels directing liquid towards the nucleating region. High speed images indicated distinct vapor columns over the nucleating regions with liquid channeled through the feeder channels.