Innovative use of low-frequency ultrasound for particle separation/classification: Forces acting on a single particle held in water of 20-kHz-ultrasound pressure fields in transition states under control of the acoustic pressure amplitude

Finding the values of the frequency and sound pressure of an acoustic wave, which ensures the process of loosening loam soil, is a very important task. We assumed that the value of the average sound pressure at which the intensity of the cavitation process would be maximum is equal to twice the value of the hydrostatic pressure. The minimum radius of the formed bubble is directly proportional to the doubled surface tension of the soil solution and inversely proportional to the ultimate compressive strength of soil. The value of the ultimate compressive strength of loam soil depends on its absolute moisture content. The angular frequency of the sound field is directly proportional to the tillage depth and the ultimate compressive strength of the soil, and inversely proportional to the sound wave propagation speed and the surface tension of the soil solution. With a loam soil density ρ=1554 kg/m3 and a tillage depth h=0.3 m, the average sound pressure was PA=9324 Pa. In the interval of physical ripeness of loam soil, the oscillation frequency of the sound field was in the range of 19 762 to 37 773 s-1.

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“…The analysis of expression (1) showed that the criterion ߯ takes a maximum value under the following condition:…”

Section: Methodsmentioning

confidence: 99%

“…The cavitation process can be of two types: hydrodynamic and acoustic [1,2]. Hydrodynamic cavitation occurs due to a local decrease in pressure in a fluid flow when it goes around a solid body.…”

Section: Introductionmentioning

confidence: 99%