Вісники НТУ "ХПІ"
Постійне посилання на розділhttps://repository.kpi.kharkov.ua/handle/KhPI-Press/2494
З 1961 р. у ХПІ видається збірник наукових праць "Вісник Харківського політехнічного інституту".
Згідно до наказу ректора № 158-1 від 07.05.2001 року "Про упорядкування видання вісника НТУ "ХПІ", збірник був перейменований у Вісник Національного Технічного Університету "ХПІ".
Вісник Національного технічного університету "Харківський політехнічний інститут" включено до переліку спеціалізованих видань ВАК України і виходить по серіях, що відображають наукові напрямки діяльності вчених університету та потенційних здобувачів вчених ступенів та звань.
Зараз налічується 30 діючих тематичних редколегій. Вісник друкує статті як співробітників НТУ "ХПІ", так і статті авторів інших наукових закладів України та зарубіжжя, які представлені у даному розділі.
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Документ Experimental study of cavitation-hydrodynamic luminescence in gas-liquid environment(Національний технічний університет "Харківський політехнічний інститут", 2021) Nochnichenko, Igor; Kryvosheiev, Vladyslav; Jakhno, Oleg; Luhovskyi, OleksandrThe article presents the results of the study of cavitation processes in technological equipment related to analytical phenomena that are accompanied by cavitation. One of the important factors accompanying cavitation processes is hydrodynamic luminescence. The information analysis of the existing theories of luminescence formation, including at hydrodynamic processes in liquids and gas-liquid environments is carried out that allowed to substantiate the basic conditions which provide emergence of the phenomenon of hydroluminescence. A literature search revealed that there is no unambiguous theory of the nature of sonoluminescence and hydroluminescence. These processes have several theories of their origin: thermal, electrical, quantum and even nuclear. Moreover, each theory is to some extent confirmed by the experiments of scientists, but at the same time is not fully disclosed. This ambiguous interpretation leads to the conclusion that the current situation cannot be considered satisfactory. Detailed experimental studies of this phenomenon are needed. For the practical study of the mechanisms of hydrodynamic luminescence, an experimental stand based on a hydrodynamic cavitator was developed and manufactured. This stand allows to investigate the cost characteristics of the cavitator, to observe and make photo and video fixation of the phenomenon of hydroluminescence in the flow of liquid or gas-liquid mixture, for which an ejector mixer was used. As a result of application of experimental-analytical method and technical visualization it is established that the phenomenon of hydroluminescence begins at an oil pressure of 20 bar, and at its saturation with inert gas – occurs at much lower pressures within 10 bar. According to our observations, with increasing flow velocity in the narrowing region, cavitation first occurs, then, with a further increase in the flow velocity, single sparks begin to appear, and at some point there is a "breakdown" and a stable glow. Based on the results of processing and analysis of experimental studies, a conceptual model of the stages of origin and development of the cavitation process and the accompanying effects is built. The conducted researches allowed to reveal the cavitation zones arising in the cavitator. Cavitation areas were identified with the help of high-speed video recording and the mechanism of its development was investigated. In addition, the visualized characteristics of the closed volume to some extent clarify the existing ideas about the behavior of the liquid and gas-liquid mixture in the nozzle. It is concluded that the phenomenon of hydroluminescence (triboluminescence) can be used as a method of cavitation visualization. At the same time, the management of workflows that accompany the phenomenon of cavitation is quite relevant because it allows you to deal with the undesirable consequences of cavitation.Документ Visualization of hydrodynamic processes in a two-pipe hydraulic shock absorber in the study of the cavitation transfer phenomenon(Національний технічний університет "Харківський політехнічний інститут", 2020) Nochnichenko, Igor; Uzunov, Oleksandr; Belikov, Kostiantyn; Haletskyi, OleksandrThe work processes that occur in the chambers of a double-tube hydraulic shock absorber during its operation are considered, such as the flow of working fluid through the piston valve, which is caused by the pressure difference between the working chambers. When the working fluid was flowing in the valve-throttle tract, in throttle operation, where only calibrated holes are used, hydrodynamic cavitation was poorly developed, which corresponds to a piston speed of about 0,25 m/s. It should be noted that when operating in a valve mode of operation, when the liquid flows through the open valves, at critical and close to critical operating modes of the hydraulic shock absorber, developed hydrodynamic cavitation occurs. In this regard, the operating characteristic changes, due to the occurrence of a two-phase flow, which is due to the presence of air, which leads to a decrease in the resistance force and a deterioration in the efficiency of vibration damping by a hydraulic shock absorber. To ensure the expansion of the range of effective operation, the operating modes were precise in which hydrodynamic cavitation occurs. One of the effective methods for fixing the occurrence of hydrodynamic cavitation is the visualization of working processes in the chambers of a hydraulic shock absorber. An experimental stand was developed and a prototype was manufactured made it possible to carry out the necessary experimental studies and establish the operating modes and the depth of the occurrence of cavitation. The study of the piston valve operation by visualizing the flow in the "rebound" mode made it possible to obtain the dependences of the flow rate on the Reynolds number and temperature, presented in the pressure range of 1–4 MPa. The experimental study also takes into account the change in the viscosity of the liquid in the temperature range from 20 °C to 50 °C. The results of the experimental study showed the weakest elements of the piston valve, and their analysis made it possible to determine the critical parameters at which hydrodynamic cavitation occurs in the shock absorber. Research in the future will make it possible to modernize the design of the valve-throttle tract to prevent the premature occurrence of hydrodynamic cavitation, taking into account changes in the viscosity of the working fluid and operating conditions. As a result of expanding the range of effective operation and the development of a control law for the conductivity of the throttles, taking into account cavitation phenomena and changes in the rheological properties of the hydraulic shock absorber fluid, it will be possible to develop a technical solution that will significantly improve the efficiency of vibration damping and stabilize its performance.