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The article presents studies on ultrasonic drying of agglomerated cork plug samples. It was revealed that the ultrasonic standing wave mode provides an increase in the drying speed compared to the traveling wave mode. It has also been shown that the energy of ultrasonic vibrations is absorbed in the cork material. In this case, the temperature inside the sample is 10 °C higher than on its surface. This helps to increase the rate of moisture release from the internal layers to the surface of the sample due to thermal diffusion.

The article presents the results of experimental studies of the process of ultrasonic drying of textile wool. It was found that additional ultrasonic exposure makes it possible to accelerate convective drying up to 7.5 times under constant initial experimental conditions. When cotton wool is exposed to ultrasound, thermal diffusion occurs. Water molecules move from the more heated center of the drying object to the less heated surface.

The article presents the results of a study of the ultrasonic drying process which is a promising way to intensify the process of moisture removal at low temperatures. An experimental stand was developed for the research. The stand is an ultrasonic dryer with automatic maintenance of the set temperature. A flexural-oscillating disk radiator was used as a source of ultrasonic action. The conducted studies have shown that changing the speed of the drying agent from 0.1 m/s to 0.2 m/s during convective drying can slightly reduce the drying time from 100 minutes to 90 minutes (10%). Change of the speed of the drying agent from 0.1 m/s to 0.2 m/s allows reducing the drying time by 10 minutes, from 80 minutes to 70 minutes with ultrasonic action. Due to the ultrasonic exposure at a drying agent speed of 0.2 m/s, the drying time is reduced from 90 minutes to 70 minutes. At a drying agent temperature of 400C, the drying time is reduced by 25% due to ultrasonic exposure (from 160 minutes to 120 minutes).

A physical and mathematical model of ultrasonic destruction and deformation of solid soil has been developed, taking into account the presence of additional influences (low-frequency impact, rotational). The numerical implementation of the model is carried out in the form of a computer program for calculating the process of deformation and destruction of the soil. The presented results of calculations proved the possibility of additionally increasing the efficiency of ultrasonic drilling by more than 2.5 times due to the imposition of low-frequency shock-contact action.

The article is devoted to investigation of energy-efficient moisture removal from capillary-porous materials. Moisture is removed by dispersion at collapse of cylindrical cavitation bubbles, formed by ultrasonic vibrations in the capillaries of the material. Mathematical model, which allowed to investigate the mechanism of moisture dispersion, has been developed. Necessity of realization of cavitation bubble full life cycle in capillary (slow growth, rapid expansion with deformation, collapse) was found. An optimal range of sound pressure levels from 150 dB ("critical level" at which dispersion of water from capillary starts) up to 170 dB (dispersion productivity growth stops due to cavitation bubbles reaching maximum size equal to diameter of capillary) was determined. It is shown that the size of the dewatered sample for maximum drying efficiency should correspond to the ultrasonic wavelength in air. Ultrasonic dispersion of liquid during drying was confirmed experimentally. It is found that for significant reduction of drying time (up to 50% and more) it is necessary to affect in the range of 165–170 dB. And the materials to be dried must be placed as particles or layers having dimensions or thicknesses corresponding to the length of the ultrasonic wave in air. The implementation of ultrasonic drying, on the example of food products (beets) provided a reduction in drying time of 1.9 times, while reducing energy costs by 1.7 times in comparison with convective drying. [ABSTRACT FROM AUTHOR]