Browsing by Author "Pitel, J."

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Effect of erosion on surface roughness and hydromechanical characteristics of abrasive-jet machining
(Sumy State University, 2024) Baha, V.; Pitel, J.; Павленко, Іван Володимирович; Pavlenko, Ivan Volodymyrovych
The article contains the fundamental results of the experimental and numerical investigations for pneumoabrasive unit nozzles with different geometries. The research was purposed by the pressing need to develop an inexpensive and effective working nozzle design of the air-abrasive unit which can be applied for surface processing before some technological processes are performed, as well as for surface coating, descaling after thermal treatment, processing of hollow holes of the crankshafts, smoothing of the inner surfaces of the narrow channels between the impeller blades after electric discharge machining for ultrahigh-pressure combination compressors. Several designs were considered, ranging from the simplest to those with a complicated inner channel geometry. The impact of the nozzle material and challenging inner surface application on its characteristics has also been studied. The research was done using the application of modern CFD complexes for numerical modeling of the air-abrasive mixture discharge from the working nozzle of the pneumo-abrasive unit. In addition, physical experimentation was provided. The methods applied in the research allow for profound, systematic research of spraying units operating on the air-abrasive mixture within a wide range of geometrical and mode parameters. The novelty of the gained results lies in the development of the mathematical model of the pneumo-abrasive nozzle operating process, the working out of a cheaper nozzle design, getting information about air-abrasive mixture distribution along the nozzle length, giving practical recommendations for calculation and designing a working nozzle for the jet-abrasive unit.
The influence of the design features of the submersible pump rotor on the vibration reliability
(Sumy State University, 2024) Маківський, Олексій Сергійович; Makivskyi, Oleksii Serhiiovych; Кондусь, Владислав Юрійович; Kondus, Vladyslav Yuriiovych; Pitel, J.; Сотник, Микола Іванович; Sotnyk, Mykola Ivanovych; Андрусяк, Владислав Олегович; Andrusiak, Vladyslav Olehovych; Полковниченко, Вадим Валентинович; Polkovnychenko, Vadym Valentynovych; Муштай, Максим Валерійович; Mushtai, Maksym Valeriiovych
Pumping equipment consumes about 20 % of the electrical energy produced by humankind. A significant, even drastic, reduction in the weight and size indicators of pumping equipment leads to a decrease in the cost price and, therefore, competitiveness of such products in the market. Simultaneously, it makes it possible to use more valuable and high-quality construction materials and technologies that improve the reliability of equipment and its energy efficiency, which in turn is a clear step in solving many UN Sustainable Development Goals (SDGs). According to the research results, it was proved that by increasing the frequency of the drive, it is possible to reduce the mass and size indicators of the submersible pump for the needs of the critical infrastructure sector by reducing the number of stages. Mainly, the amplitudes of oscillations near the rotation frequency are 12–22 % and do not exceed 35 % of the gaps in the seals, as required by the available international standards to ensure the guaranteed vibration reliability of the pump. Overall, using a bearingless support design will significantly increase the reliability of the developed pump.
Numerical Simulation of Gas Flow Passing through Slots of Various Shapes in Labyrinth Seals
(MDPI, 2022) Бага, Вадим Миколайович; Бага, Вадим Николаевич; Baha, Vadym Mykolaiovych; Lishchenko, N.; Ванєєв, Сергій Михайлович; Ванеев, Сергей Михайлович; Vanieiev, Serhii Mykhailovych; Mizakova, J.; Родимченко, Тетяна Сергіївна; Родимченко, Татьяна Сергеевна; Rodymchenko, Tetiana Serhiivna; Pitel, J.
Labyrinth seals are widely used in centrifugal compressors, turbines, and many other pneumatic systems due to their simplicity of design, reliability, and low cost. The calculation scheme for the movement of the working medium in a labyrinth seal is constructed by analogy with the movement of the working medium through holes with a sharp edge. Annular and flat slots, holes, and such a factor as the shaft rotation with a calculated sector of 3 degrees were studied. The purpose of the study is to determine the flow coefficient when the working medium flows through slots of various shapes. To achieve this purpose, modeling of the working medium flow in the FlowVision software was performed. The mass flow and flow coefficients are determined for the studied slot shapes. The convergence of the calculation results was determined by comparing the values of the mass flow rate at the inlet and outlet of the slot. Differences in visualizations of the flow for the studied variants of slots were established. The resulting difference should be taken into account in practical calculations of the working medium mass flow through the slot using a conditional flow rate factor which is determined by the slot design.