Generation and maintenance of bubbles in small tubes by low-frequency ultrasound

摘要: A system has been developed to generate and maintain a bubble population in nonscattering fluid media within small 1.3-mm (i.d.) transparent silicone tube by use of low-frequency ultrasound at 28.8 kHz. The uses sequence three different kinds acoustic cavitation processes: transient, stable cyclic. In the final step sequence, low-duty cycle (∼10%) low-pressure (∼30 kPa) is used microbubble whose mean diameter ∼12 μm, which can be as Doppler scatterers. To understand measure behavior bubbles for processes tube, CCD imaging synchronized short duration flash were capture movie frame sequences. Subsequent analysis frames enabled following parameters measured: size distributions, fractional volume concentration, flow characteristics, rise velocity, dissolution time, growth rate various formation processes. addit...