Aerodynamic parameters features of air flows in ventilation pipes of underground mining workings

Introduction. The article discusses the features of gas flow in T-shaped pipeline connections, which are widely used in many industries and farms, such as underground mining, energy, water supply, and pneumatic transmission systems. A study of the aerodynamic characteristics of air flows in channels of different diameters connected by a tee has been conducted, and the problems and prospects of improving the efficiency of ventilation equipment in mining enterprises by optimizing air supply processes in the design process, taking into account flow aerodynamics, have been analyzed. The purpose of the study. Study of the aerodynamic parameters of air flows in pipeline connections with a mixing tee that simulates ventilation flows in mining conditions. Methods and materials. A stand has been developed for the empirical study of the aerodynamic drag of systems with tees, including systems for measuring the aerodynamic properties of the flow, systems for measuring the flow rate through the channel with flow preparation devices and systems for constructing a velocity profile. Using the methods of digital and physical modeling on an experimental stand, the processes of the movement of matter through mixing tees and the analytical calculation of the dependence of the loss value at different cost ratios were studied, the mathematical model was verified, and the accuracy of the results was evaluated. Results and discussion. As a result, graphical dependences of the value of the pressure loss coefficient on the ratio of the flow rates of substances in the channels for a nozzle-type device and a direct channel are obtained. The mathematical model has been verified with a physical test bench: the average absolute and RMS error do not exceed 0.5 for both the piezometric line and the velocity profile, and the values of the Pearson and determination correlation coefficients do not deviate from the value of 1 by more than 0.01. Conclusions. The article presents the results of studies of the aerodynamic characteristics of collecting tees of complex shape, taking into account the swirlers: the values of the coefficient of resistance of the mixing tee for a device such as a nozzle and a straight channel at different flow rates. Resume. The research results can be useful in designing ventilation and degassing systems of underground mine workings, tunnels, and construction structures, improving the efficiency of their operation and the safety of the production process. The proposed integrated approach, including experimental measurements and mathematical modeling, is capable of improving the accuracy of measurements of the aerodynamic characteristics of gas flows in widespread T-types of mixing pipelines.