The dynamics of a single bubble formed on a micro fabricated cavity was experimentally investigated at different orientations of the heater surface with respect to the horizontal. Water at one atmosphere pressure was used as the test liquid and the cavity was formed on a ribbon made out of a Silicon wafer. The flow velocities along the heater surface were parametrically varied from 0.07 to 0.25 m/s. The wall superheats and liquid subcoolings were also varied, but over a limited range. It was found that in all cases except for an upward facing horizontal surface with no imposed velocity, bubbles slid along the surface before lifting off normal to the surface. The diameter at which bubbles begin to slide is found to be only dependent on the flow velocity. However, the bubble lift off diameter is found to depend both on orientation of the surface and flow velocity. These results have provided a clear evidence of the role played by the lift force in the detachment of bubbles from the heater surface.
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