Determination of the influence of the sound capillary effect on the process of soaking vegetable raw materials in the acoustic extractor

Abstract

The object of research is the process of liquid movement in capillaries during the extraction of biologically active substances (BAS) from plant raw materials under the action of the sound capillary effect. A characteristic feature of vegetable raw materials is a large number of pores of the capillary type. Penetration of the extractant into the raw material occurs through capillaries and leads to the filling of cells and voids in it. The process of filling the capillaries and cell voids with the extractant can be quite long and significantly increase the extraction time as a whole. It was established that the penetration of the extractant into the capillaries of plant raw materials is affected by ultrasonic vibrations that cause cavitation. Under the action of cavitation, which occurs in the ultrasonic field, the penetration of the extractant into narrow cavities and crevices is accelerated and deepened. This phenomenon is called the sound capillary effect. The analysis of literary sources showed that there are no data on the study of the conditions for the occurrence of the sound capillary effect and the effect on the speed of movement of liquid in the capillaries of ultrasonic pressure during the BAS extraction from plant raw materials. Numerical modeling was used to study the movement of liquid (extractant) in capillaries during the BAS extraction from plant raw materials under the conditions of ultrasound. As a result of the conducted research, the conditions for the occurrence of ultrasonic cavitation in the process of BAS extraction from plant raw materials with the most common extractants, such as water and ethanol solutions, were found. The values of the amplitude of the sound pressure of the extractant, which occurs under the conditions of the sound capillary effect directly at the entrance to the capillary, were also found. The dependences of the sound capillary pressure on the diameter of the capillary for the most common extractants have been established. The influence of the sound-capillary effect on the speed of movement of the most common extractants in capillaries of different sizes is determined. The obtained research results allow to quantitatively evaluate the influence of the sound-capillary effect on the movement of extractants in the capillaries of plant raw materials, on the rate of wetting of plant raw materials and the speed of mass exchange processes during extraction. These results can be used when choosing operating modes of existing and designing new equipment for the BAS extraction from plant raw materials under ultrasound conditions.