A Hydrodynamic Analysis of the Dead-End Lines of Hydraulic System Pressure Mains Taking into Account High-Frequency Pressure Pulsations

Hydrodynamic analysis with the aid of numerical modeling tools is widely used in the design and modernization of hydraulic systems of aircraft, as well as in the analysis of the causes of depressurization, local destruction, and so on. This analysis includes both the operation of the hydraulic system in different modes, and the process of switching from one mode to another. However, in the scientific literature there is no information that would take account of high-frequency pressure pulsations from the hydraulic pump in the dead-end lines of hydraulic systems, and their possible impact on the pipelines and attachment points to the elements of the airframe. In the scope of this research, the possibility of low-frequency resonance in the dead-end lines of hydraulic systems is determined. A technique for setting and performing finite-volume modeling and hydro-gasdynamic analysis is described. The results of the analysis of the eigenfrequencies of oscillations in prefabricated structures of the hydraulic system pressure lines are presented. It is proven that the frequency of the resulting low-frequency resonance of the hydraulic fluid pulsations does not correspond to any of the eigenfrequencies of oscillations of the structural elements, and is, therefore, forced. The need for further assessment of the degree of influence of the described phenomenon on the operational life of the attachment points to the elements of the airframe is highlighted.

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