No abstract

At present, ultrasonic (piezoelectric) transducers are the most promising electromechanical transducers for use in miniature electronic devices. However, the calculation of the piezoelectric element for an ultrasonic environment poses certain problems due to the large number of problems to be solved and its nonlinearity. The article describes the principles of operation of the piezoelectric element, analyzes their advantages and disadvantages, gives the characteristics of the piezoelectric elements, as well as proposes an algorithm for calculating the frequency characteristics of the piezoelectric element based on the electrical model of the piezoelectric element.

Three mathematical models were used in this study: the Newton model, the Henderson-Pabis model, and the Page model. Three models were chosen for comparison with experimental data because they are commonly used to describe the drying characteristics of thin films and are simplifications of the theoretical model derived from the diffusion equation (Fick’s second law). The Newton model is a mathematical model for drying a thin layer, also called the Lewis model. Lewis described that the transfer of water from food and foodstuffs can be shown by analogy with the outflow of heat from the body when the body is immersed in a cold liquid. The Henderson-Pabis model has been used in thin-layer drying of various agricultural products, including drying of corn, wheat, coarse rice, beans and tubers. The Page model is a modified model of the Lewis model. Page proposed this model to correct the shortcomings of the Lewis model. Page’s model has created models that are suitable for describing the drying of various agricultural products and are easier to use than other equations.

The design and operation of electronic generators for ultrasonic intensification of processes in gaseous and liquid media will be considered. General requirements and new approaches to electronic generators have been developed based on the analysis of the characteristics of modern piezoelectric vibration systems that perform large amplitude oscillations (quality factor, multi-frequency, multilayer piezoelectric elements). Continuous monitoring of system parameters and setting of optimal operating modes of the electronic generator were studied.

The article examines the solar collector of a solar water heating dryer using the example of drying ginger root (Zungiber). The diagram of a solar water heating drying unit is presented. The useful energy and temperature coming from the solar collector were analyzed using the model. The graphs are compared with the experimental results.