Micro-bubble controlled growth in rectangular microchannel of micro-electro-mechanical systems

With the silicon microfabrication process, six micro-electro-mechanical systems (MEMS) devices for exploring micro-bubble growth were designed and fabricated. Experimental investigations of micro-bubble growth in micro restrained space were performed. The results showed that the micro-bubble growth rate was influenced by heat power, dimensions of microheater, microchannel section, microfluidic velocity, and materials of the fluid. A higher heating voltage resulted in faster bubble growth. The width of heating pulse took effect during the latter period of bubble growth. Under the same heating voltage and pulse width, a larger width of the microheater led to faster bubble growth. When the aspect ratio of the microchannel section was over 1.0, a smaller aspect ratio brought on slower bubble growth during the latter period. The larger the microfluidic velocity, the later the bubble growth start point, and the slower the bubble growth. Under the same test condition, the bubble growth rate of R113 was the largest among the three working fluids, followed by FC-72 and deionized water, due to the effect of thermophysical parameters of the fluids.