The aggregation of suspended particles in gases by sonic and supersonic waves

Ultrasonic agglomeration and preconditioning of aerosol particles for environmental and other applications

“…The linear mechanisms involved in the agglomeration process have been extensively studied (Andrade, 1936;Brandt and Hiedemann, 1936;Mednikov, 1965;Shaw, 1978;Shirokova, 1973;Temkin, 1994). The basic effect of producing particle collisions is due to the different acoustic entrainments that the vibration induces in particles of different size and weight.…”

“…Orthokinetic interaction (Brandt and Hiedemann, 1936) occurs between two or more suspended particles of different sizes when they are located within a distance approximately equal to the displacement amplitude of the sound field in the suspending medium and their relative motion is substantially parallel to the direction of vibration. Because of the differential fluid and inertial forces, the particles vibrate with different amplitudes and phases and such differential motion greatly increases the probability of collision and, therefore, of agglomeration.…”

Modelling of acoustic agglomeration processes using the direct simulation Monte Carlo method

“…The orthokinetic mechanism has been well explained through the experimental and theoretical studies carried out by e.g. Brandt and Hiedemann (1936), Mednikov (1965), Song (1990), Temkin (1994), Hoffmann (1997), and others. Hydrodynamic interaction takes place between particles of the same or different size and the agglomeration is caused by the hydrodynamic forces resulting from the mutual distortion of the flow fields around the particles close to each other.…”

Experimental Parametric Study of Frequency and Sound Pressure Level on the Acoustic Coagulation and Precipitation of PM2.5 Aerosols

“…Patterson and Cawood performed a similar experiment in gaseous medium and for the first time observed acoustic agglomeration in standing waves in 1931 (Patterson and Cawood, 1931). In Germany, independent investigations were conducted by Brandt and Hiedemann (Brandt and Hiedemann, 1936). They checked different frequencies and found that acoustic coagulation in the hearing range frequencies is better carried out than that in the ultrasonic ones.…”