抄録
A visualization and pressure drop measurement in 0.5 x 0.5mm rectangular microchannels were carried out to investigate the flow instability and flow reversal, which are observed frequently in flow boiling in mini-/microchannels. Among the complicated system, the current study focused on the behaviors of the departing bubble size and two-phase flow pattern that may be influenced by the size of nucleation sites and nucleated bubbles, respectively. The experiments were carried out in adiabatic condition in order to examine the pure dependence of the departing bubble size on the nucleation site characteristics and of flow on the nucleated bubbles, and therefore, air was introduced from holes in the test channels instead of the bubbles nucleated from the nucleation cavities. Holes with two different diameters and two different wettabilities were examined.
