Browsing by Author "Ponomarenko, Serhii M."

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    A Mathematical Model for the Determination of the Parameters of a Gas in an Open Thermodynamic System in Contact with the Environment
    (Seventh Sense Research Group, 2025) Ponomarenko, Serhii M.; Zhevzhyk, Oleksandr V.; Potapchuk, Iryna Yu.; Kabakova, Liudmyla B.; Yelatontsev, Dmytro O.
    ENG: Leaks in gaseous storage and supply systems impose security and economic threats that are influenced by the heat exchange. A methodology is proposed to assess thermodynamic changes in a leaky system utilizing a mathematical model for the "pipe-hole" scenario based on the Poiseuille equation for laminar gas leakage with a capillary diameter below 0.1 m. Differential equations are derived to analyze the time-dependent thermodynamic variations of compressed air in the “pipe-hole” system via the energy balance equation. A mathematical model was developed for general case studies of open thermodynamic variable-mass gas systems. The FORTRAN software tool was used to solve the system of differential equations using the Runge-Kutta method, with four orders of accuracy. A specific examination was conducted on a thermodynamic system that lacks a constant gas supply and stationary convective heat exchange in a single-layer gas container with the environment. The ranges of the control parameter variation were considered as follows: air pressure p0 from 150 kPa to 300 kPa and temperature Ta from 15 ◦C to 25 ◦C. This study reveals how the density, pressure, and temperature of compressed air vary over time owing to leakage and heat fluxes. It was determined that as initial air pressure decreases from р0 = 150 kPa, the impact of heat flow rates markedly surpasses that of air leakage rates. A potential application of this research could be the software for monitoring devices for high-pressure systems designed for the storage and distribution of gaseous energy carriers.
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    Patterns of Air Mixture Movement in the Operating Area for the Annular Ejector of Pneumatic Transportation System
    (НТУ «Дніпровська політехніка», Дніпро, 2023) Ponomarenko, Serhii M.; Potapchuk, Iryna Yu.; Kabakova, Liudmyla B.; Radchenko, Yurii M.
    ENG: Purpose. To establish the regularities of two-phase flow of “gas-solid particles” in the operating area of an annular ejector where the following processes take place: air mixture ejecting, compressed air outflow from the ejector nozzle, air mixture flows mixing in the transport pipeline. In the work, the velocity distribution is also examined for dispersed phase and air phase of air mixture during its loading and accelerating in the transport pipeline of the pneumatic transport system. Methodology. The research is based on the fundamental approaches of mass point dynamics, aerodynamics, the theory of jet flows and iteration methods of numerical solution of equations. Findings. The mechanics of the air mixture flow under the ejection and aerodynamic force in the operating area of an annular ejector and at the beginning of transport pipeline is analyzed using the method of iterations. The impact of air mixture flow in the operating area of an annular ejector on energy performance of the pneumatic transport system is evaluated. Originality. The originality is that, for the first time, the regularities describing two-phase “gas-solid particles” flow at the loading area of the pneumatic transport system with an annular ejector have been obtained. This made it possible to characterize the velocity distribution of the dispersed and air phases of the air mixture during their loading and aerodynamic acceleration in the transport pipeline. Also, an innovative approach to the effectiveness of the use of pipeline pneumatic transport is the assessment of the energy indicators of the use of ejector-type pneumatic transport equipment depending on the rate of compressed air outflow from the ejector. Practical value. The implementation of the results in the modernization of existing and in the creation of new pneumatic transport systems with an annular ejector makes it possible to increase the efficiency of their use in the technological processes of moving dispersed materials at mining and metallurgical enterprises and in other areas of technology.