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The economical combustion of gas fuel implies that it takes place with a minimum coefficient of excess air and minimal losses. Constructive, aerodynamic and physical factors have a determining influence on the completeness of combustion and the conditions of ignition. Using the ANSYS software program, the main characteristics of the combustion process in the cylindrical mixing section of a flat flame injection burner are investigated through computer simulation. A geometric model was created on which it is possible to study both straight and rotating jets. The possibility of numerically investigating the combustion of gaseous fuel (C 3 H 8 ) in a confined air flow produced by injection is considered. A k-ε model of turbulence was used, which is based on the equation for turbulent kinetic energy and its dissipation rate. The purpose of the work is to study and analyze the changes and distribution of temperature and speed as well as the concentration of nitrogen oxides and carbon monoxide along the axis of the combustion chamber. The results are presented for the angles of inclination of the nozzles of 45° and 0°. Based on these, an analysis was made, where it 22 was found that with the increase in the degree of rotation, the absolute values of the temperature increase and the change in the mass concentration of the fuel along the length of the mixing section can be used to regulate the combustion process. The created numerical model can be successfully used to determine the main parameters of the burner under the same initial conditions, changing the angle of inclination of the nozzles. The obtained results can be considered as a basis for further research related to increasing the efficiency of the combustion process and lowering the harmful emissions produced by it.

Wave energy from seas and oceans is among the most promising and abundant energy sources on the Earth. There are different designs of conversion systems for the utilization of the wave energy, resulting from the different ways of the wave energy absorption, and depending on the location characteristics. The paper proposes a new hydraulic power take-off system (PTOS) that can be used in various types of wave energy conversion systems.

Increasing consumption of meat and meat products worldwide is closely linked to improving the living environment for livestock. According to zoo experts, the appropriate microclimate in buildings leads to improved metabolic processes in their cultivation and contributes to their rapid weight gain. The issue of raising new-borns and young animals is especially relevant. Achieving optimal parameters of the microclimate in the premises, together with the necessary veterinary care for new-borns reduces stress and mortality in them. The above requires the implementation of new and modern engineering solutions in the design and construction of livestock buildings. The use of numerical simulations, through CFD programs for modelling and solving engineering problems, as well as the creation of adequate mathematical models, is a prerequisite for reducing the time and resources to solve a problem. Based on the accumulated experience of the authors on the microclimate in livestock farms in this publication, a numerical simulation of air exchange in a livestock building for breeding sows with young piglets is presented. The physical model, research and analysis are realized in the middle of Ansys Fluent. Two models of air exchange organization in the livestock building are proposed. The obtained data on the temperature and speed fields in the building will lead to an improvement of the microclimate in the considered site. In addition, they could serve as a basis for conducting the next series of computer simulations. The built models can be adapted for other building constructions for breeding other types of animals. The analysis of the data and a more in-depth examination of the factors related to animal husbandry could help to increase pork yields on livestock farms