THERMAL SCIENCE

International Scientific Journal

Darko M. Knežević

,

Aleksandar N. Milašinović

,

Zdravko N. Milovanović

,

Saša S. Laloš

THE INFLUENCE OF THERMODYNAMIC STATE OF MINERAL HYDRAULIC OIL ON FLOW RATE THROUGH RADIAL CLEARANCE AT ZERO OVERLAP INSIDE THE HYDRAULIC COMPONENTS

ABSTRACT
In control hydraulic components (servo valves, LS regulators, etc.) there is a need for precise mathematical description of fluid flow through radial clearances between the control piston and body of component at zero overlap, small valve opening and small lengths of overlap. Such a mathematical description would allow for a better dynamic analysis and stability analysis of hydraulic systems. The existing formulas in the literature do not take into account the change of the physical properties of the fluid with a change of thermodynamic state of the fluid to determine the flow rate through radial clearances in hydraulic components at zero overlap, a small opening, and a small overlap lengths, which leads to the formation of insufficiently precise mathematical models. In this paper model description of fluid flow through radial clearances at zero overlap is developed, taking into account the changes of physical properties of hydraulic fluid as a function of pressure and temperature. In addition, the experimental verification of the mathematical model is performed.
KEYWORDS
radial clearances, discharge coefficient, density, viscosity, thermodynamic change of state of the fluid
PAPER SUBMITTED: 2016-05-17
PAPER REVISED: 2016-07-20
PAPER ACCEPTED: 2016-07-28
PUBLISHED ONLINE: 2016-12-25
DOI REFERENCE: https://doi.org/10.2298/TSCI16S5461K
CITATION EXPORT: view in browser or download as text file
THERMAL SCIENCE YEAR 2016, VOLUME 20, ISSUE Supplement 5, PAGES [S1461 - S1471]
REFERENCES
  1. Bašta, T. M., Mašinska hidraulika, (Mechanical Hydraulics - in Serbian), Faculy of Mechanical Engineering, Belgrade, 1990
  2. Borghi, M., et al., Analysis of Hydraulic Components Using Computational Fluid Dynamics Models, Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 212 (1998), 7, pp. 619-629
  3. Wu, D., et al., An Empirical Discharge Coefficient Model for Orifice Flow, International Journal of Fluid Power, 3 (2002), 3, pp. 13-19
  4. Knežević, D., et al., Mathematical Modeling of Changing of Dinamic Viscosity, as a Function of Temperature and Pressure, of Mineral Oils for Hydraulic Systems, Facta Universitatis, 4 (2006), 1, pp. 27-34
  5. Stachoviak, G., et al., Engineering Tribology, University of Western Australia, Perth, Australia, 2001
  6. Keith, P., et al., Hydraulic Fluids, Arnold, UK, 1996
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THE INFLUENCE OF THERMODYNAMIC STATE OF MINERAL HYDRAULIC OIL ON FLOW RATE THROUGH RADIAL CLEARANCE AT ZERO OVERLAP INSIDE THE HYDRAULIC COMPONENTS

© 2024 Society of Thermal Engineers of Serbia. Published by the Vinča Institute of Nuclear Sciences, National Institute of the Republic of Serbia, Belgrade, Serbia. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International licence