Pressure controlled bubble growth in microchannels

As microfluidic devices are used with high-pressure fluids, the effects of liquid compressibility become important for understanding system behavior. Bubble growth in a microfluidic channel, for instance, is qualitatively different in a rigid fixed-volume high pressure microfluidic device than it is in a flexible or open microfluidic device. With a fixed volume, bubble growth must be accompanied by compression of the surrounding liquid, increasing the system pressure. Increased pressure decreases the diffusion drive, slowing bubble growth. A nonlinear equation for system pressure is derived relating these coupled effects. This equation is linearized in the limit of small supersaturation, yielding a closed form solution. For larger supersaturations, the governing equations are solved numerically. Experiments on bubble growth in gas saturated liquid agree well with this one-dimensional model.