The Limits of Fine Particle Ultrasonic Coagulation

Abstract

This paper describes the studies conducted in order to identify the limits of ultrasonic exposure’s effect on the fine particle coagulation process. It has been established as a result of the studies that ultrasonic exposure with a sound pressure level of 160 dB is capable of ensuring coagulation of particles sized 2.5 µm with efficiency δ = 83%. An increase of the coagulation up to 13% is induced with generation of swirling flows. The suggested approach to increasing the coagulation efficiency owing to vortex-type flows between the radiating and reflecting surfaces ensures efficiency of coagulation δ = 96 %. The implementation of this approach has shown that with generation of vortex-type acoustic flows, it makes the most sense for a concentration of particles of 18×10−3 g/m3. Incremental efficiency at such concentrations amounts to 50%.

Agglomeration of aerosol using small equipment with two small aerial ultrasonic sources

“…19,20) Gallego-Juarez et al constructed an experimental apparatus (about 5 m 3 in volume) using an ultrasonic source consisting of a stepped vibrating plate that produced transverse vibrations and showed that the mass concentration of fine particles was reduced to one-tenth in 15 min at a power of 400 W. [21][22][23] Khmelev et al showed that an ultrasonic system with a piston radiator agglomerated 83% of PM 2.5 particles at a sound pressure level of 160 dB. 24,25) They also showed that a combination of inertial dust collection and an ultrasonic vibration system with a volume of about 0.06 m 3 agglomerated 85% of PM 2.5 particles. 26) Houda et al conducted agglomeration experiments using a cylindrical vibrating plate ultrasonic source 27) with constant input power and obtained an 86% agglomeration efficiency at a total input power of 20 W. 28) The volume of the agglomeration section of this device was about 1500-2500 cm 3 .…”

Symmetry in Aerosol Mechanics: Review

“…Coagulation is accelerated in turbulent flows [48], under the action of acoustic waves [49,50], under the combined action of ultrasound and vortex motion. Such a combined effect is successfully studied in the works of Khmelev et al [51][52][53].…”

Излучатели Для Формирования Высокоинтенсивных Ультразвуковых Колебаний В Газовых Средах Различного Назначения

“…формирование стоячей волны, вследствие чего в существенно возрастает уровень звукового давления. Таким образом, в пространстве между излучателем и отражателем может быть реализован процесс коагуляции высокодисперсных частиц [10].…”

“…Решениям указанной проблемы может служить создание нового типа излучателей представляющие собой изгибноколеблющиеся диски [8]. Колебания таких излучателей на заданной моде на частотах более 22 кГц с уровнями давления до 170 дБ формируются последовательно установленными и пьезоэлектрическими преобразовате-лями [4,10]. Дисковые излучатели могут иметь размеры излучающих поверхностей более 1 м 2 и способны осуществлять вывод в воздух до 60% от энергии, затрачиваемой на формирование ультразвуковых колебаний.…”