Bubble Dynamics for Explosive Microthermal Dual Bubbles

Bubble dynamics of explosive microthermal dual bubbles including the growth and collapse process are investigated experimentally in detail. The dual bubbles are generated with supplied heat flux of 1.61 GW/m² on two 30 times 60 mum² heaters. The heaters are separated by different distances ranging from 25 to 125 mum. As the heaters get closer in x-direction, higher anisotropic degree in directional extensions of dual bubbles is obtained with faster bubble expansion velocity during collapse in x-, y-, and z-directions. In addition, the bubble lifetime is shorter as the two heaters are separated more although the supplied heat flux is the same. Furthermore, one application of dual bubble system actuating the droplet formation demonstrates that the droplet formation process with no satellites can be achieved by adjusting the expansion rate of bubbles or the spacing between two heaters.