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The automation of the procedure of the electrohydraulic complex power harmonic analysis

100%

Zagirnyak M. , Kovalchuk V. , Korenkova T.

tom R. 94, nr 1

1--4

A possibility of application of the method for the harmonic analysis of power signals in the non-stationary modes of electrohydraulic complexes operation is demonstrated. To automate the procedure of power harmonic analysis an energy analyzer is created. It enables the research of the electrohydraulic complex power processes when they change in real time with preservation of all information about the initial power-forming signals. It is obtained that the wave processes in the pipeline in non-stationary modes are accompanied by increase of the power signals variable components, especially, their low-frequency component. It is proposed to use the indices based on determination of the power root-mean-square values to assess the energy conversion processes in the electrohydraulic complex.

W pracy zademonstrowano możliwość aplikacji metody analizy harmonicznych sygnałów mocy w niestacjonarnych modach układów elektrohydraulicznych. Do zautomatyzowania procesu stworzono procedurę harmonicznej analizy mocy w analizatorach energii. Umożliwia to badanie procesów w układach elektrohydraulicznych w czasie realnym, podczas ich zmiany z zachowaniem wszystkich informacji o początkowych sygnałach. Otrzymano, że niestacjonarne procesy falowe w rurociągu stowarzyszone są ze wzrostem składników sygnałów mocy, specjalnie tych o niskiej częstotliwości. Zaproponowano wykorzystanie indeksów bazujących na określeniu wartości skutecznej w celu oszacowania procesów przemiany energetycznej w układzie elektrohydraulicznym.

Mathematical modeling of nonstationary processes in engine aggregates of mud pumps

100%

Kharchenko Y.

tom nr 4(48)

61-65

The mathematical model of dynamic processes in the engine aggregate of the mud pump with the operating friction clutch is offered. Inconstancy of reduced moment of inertia of crank mechanism of the pump and also interrelation of electromagnetic effects in asynchronous engine with non-linear oscillations of mechanical system are taken into account. The integration of system of the differential equations of movement of pump is realized by numerical methods.

Increase of the technogenic and ecological safety of the natural gas transportation due to displacement of explosive mixtures with nitrogen

80%

Mandryk O. , Vytyaz O. , Poberezhny L. , Mykhailiuk Y.

tom Vol. 106, nr 1

17--27

Purpose: To ensure technological and environmental safety it is proposed to use the technology of purging pipeline with compressed nitrogen. Design/methodology/approach: The purpose of the calculation is: to get the graph of the concentration distribution (in volume fraction) of nitrogen and natural gas components depending on the distance from the injection point of nitrogen and the duration of the purge process, to determine of parameters of a non-stationary process, and to establish the optimal parameters of the purging process under conditions of the given flow chart. Findings: In the process of displacement of natural gas, the velocity of the front of nitrogen is one of the main quantities that significantly affect the quality of displacement. To assess the actual technological schemes for transporting natural gas, it is necessary to select the velocity of displacement of explosive mixtures. Research limitations/implications: This technology should be implemented in the conditions of a nitrogen pressure higher than 0.25 MPa. Practical implications: Most favourable conditions for the complete displacement of air and subsequent replacement of nitrogen with natural gas were observed for pressures higher from 1.0 to 1.5 MPa. Originality/value: Complex calculations of the volume of air displaced with nitrogen and natural gas in the process of filling the pipeline were conducted in the research. Boundary conditions on the concentration of the mixture of nitrogen and natural gas were identified.