Macrosonics in industry : 4. Chemical processing

Acoustic irradiation can result in increased inter-phase mass and heat transfer rates. The second-order acoustic effects of cavitation, interfacial instability, radiation pressure and acoustic streaming are responsible for the enhancement in these rate processes. The application of sonic and ultrasonic energy in industrial processing is reviewed. A number of units using acoustic energy to enhance rates of conventional unit processes, for example, drying, solid-liquid extraction, etc, are described. In addition, new applications in waste water treatment and oil-water emulsion fuels are described. The development of newer, more efficient generators should lead to a greater use of acoustic energy for large-scale industrial processing.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22154/1/0000585.pd

Second-order sonochemical phenomena--extensions of previous work and applications in industrial processing

The first-order properties of acoustic waves (i.e., the to and fro particle displacement and velocity) can produce a number of second-order phenomena: cavitation, acoustic streaming, surface instability and radiation pressure. The dependence of cavitation induced phenomena (erosion, luminescense, chemical reactions) on the physical and acoustical parameters of a system are discussed. Some of the past work carried out in this field is analyzed and reinterpreted. In the light of this, it appears that the extent of the solubility of a gas has a pronounced effect on cavitation related phenomena in addition to the effect of other variables such as the ambient liquid temperature, the hydrostatic pressure, the specific heat ratio, the thermal conductivity of dissolved gas and the intensity and frequency of acoustic field. A summary of the application of sonic and ultrasonic energy to industrial processing operations is also provided. This discussion includes how the other second-order effects (e.g., interfacial instability) are related to the enhancement of these operations. The wide variety of processes in which the applications of acoustic energy has a beneficial effect suggests the versatility and broad commercial potential of sonochemical engineering.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22447/1/0000899.pd