Justification of the Working Medium Model Selection for Calculation of Dynamic Parameters of Pneumohydraulic Systems

This article presents the research of properties of pneumohydraulic system models based on various equations of state. An analysis of the approaches applied to the selection of the research methods is performed, and the existing shortcomings are revealed. It is shown how the use of different equations of state (Dupre-Abel, Van der Waals, Redlich-Kwong, ideal gas) affects the accuracy of calculation of vessel filling time. For the constant volume cavity, the time of filling with gas under pressure through a hole of a constant area to the required pressure is determined in various ways. The research results are presented on an experimental stand, consisting of two vessels of 0.01 m3 and 0.003 m3, connected by a short pipeline (air with a pressure of 26 MPa is used as a working medium). The calculation and the experimental data is compared. Conclusions about the Redlich-Kwong equation of state as the most suitable for calculating the vessel filling time are made based on the theoretical and experimental studies.

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