NUMERICAL SIMULATION OF THE PROCESSES OF HYDRODTNAMICS AND HEAT TRANSFER PROCESSES IN ROTOR-PULSATION APPARATUS
Authors:   Institute of Engineering Thermophysics of National Academy of Sciences of Ukraine, Ukraine, Obodovych Oleksandr , Stepanova Olesya ,   Institute of Engineering Thermophysics of National Academy of Sciences of Ukraine, Ukraine
Published: February 2023

The development of energy-saving technologies that meet the modern requirements of product production is based on the development of new concepts, conducting comprehensive scientific research, and a detailed study of the essence of physical phenomena, which determines the possibility of purposeful management of the technological process and ensuring optimal conditions for its implementation. In the existing devices for the preparation of mixtures, grinding methods are used in hammer crushers and mills, which requires significant expenditure of mechanical (electrical) energy. Therefore, it is necessary to develop devices with a high degree of influence on the processed environment, which increases productivity and reduces energy consumption in technological processes. Such devices include rotary-pulsation devices, the principle of operation of which is based on the method of discrete-pulse energy input. The basis of this method is the multifactorial influence on the processed liquid homogeneous or heterogeneous environment, consisting of pressure pulsations, changes in the liquid flow rate, intense cavitation, developed turbulence, rigid cumulative impact, as well as high shear forces. The current task in this work is the study of the impact of discrete-pulse energy input mechanisms that take place in rotary-pulsation devices during the processing of heterogeneous media, as well as the development of new designs of devices of the specified type to obtain high-quality products. Therefore, the work is devoted to the development of a new design of the rotor-pulsation apparatus for the preparation of liquid mixtures, the principle of which is the use of a working chamber with a rotor and a stator, which have holes of different configurations. The purpose of the study is to conduct a comprehensive analysis of kinematic and dynamic characteristics and establish the features of discrete-pulse energy input during the dispersion of mixtures in a rotary-pulsation apparatus and to develop, on this basis, energy-saving technology and equipment for their preparation. Numerical modeling and experimental research of the processes of hydrodynamics and heat transfer in the mixture during its preparation were carried out. The working chamber of the device consists of a cylindrical rotor and stator containing round and rectangular perforated holes. The mathematical model includes the two- or three-dimensional Navier-Stokes equations, the κ-ε transport equation of the turbulence model, and the energy equation. Factors that affect the processes of deformation and destruction of dispersed particles in heterogeneous media processed in rotary-pulsation devices are pressure pulsations, as well as normal and tangential stress pulsations that occur in the flow when it passes through the working zone of the device. As a result of numerical studies, the fields of velocities, pressures and temperatures of the studied media were found, and the most optimal geometric characteristics of the working chamber of the rotary-pulsation apparatus were determined. Based on the obtained results of numerical simulation, the designs of the rotor-pulsation apparatus will be selected, which will be used for the production of industrial research samples of this device.