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COMPUTER HYDROMECHANICS, 2024
IX International Scientific & Practical Conference "Computer Hydromechanics"
HYDRODYNAMICS AND ACOUSTICS
2024 ◊ Volume 3 (93) ◊ Issue 1 ◊ p. 5-15
V. P. Berman*, E. Bournaski**, V. V. Fadeichev*, I. V. Skorokhod*, L. S. Orlova*
* Institute of Hydromechanics of NAS of Ukraine, Kyiv, Ukraine
** Climate, Atmosphere and Water Research Institute at Bulgarian Academy of Sciences, Sofia, Bulgaria
Numerical simulation of the unsteady fluid motion in pipelines in the pump unit start-up mode
Gidrodin. akust. 2024, 3(1):005-015
TEXT LANGUAGE: English
ABSTRACT
From the experience of operating pipeline transport systems of various incompressible and compressible viscous flows, it is known that transportation conditions are constantly changing during their operation. In turn, this causes sharp fluctuations in the characteristics of such flows, which can be dangerous to pipeline equipment and personnel. In this regard, starting from the design stage, it is necessary to have convenient methods for calculating transient (unsteady) modes of flow movement, which allow determining possible pressure and flow fluctuations in different modes of operation of transport systems. Based on them, it is possible to obtain the necessary information for calculating and selecting the pipeline protection system against excessively high pressures, as well as for adjustment of the means of automatic control and protection of the systems under consideration. The paper proposes a simple and reliable mathematical model along with the numerical method for calculating the unsteady turbulent transport of liquid flows in pipelines in the pump installation start-up mode. The model is based on a system of quasi-one-dimensional equations for describing the motion of liquid in a pipe, supplemented by the empirical dependence of the value of hydraulic resistance on time and the Reynolds number. The main problems that arise when modeling the considered unsteady flows are stated. In particular, we discuss the possibility of using a simplified system of hydrodynamic equations, the choice of numerical solution methods, and the unsteadiness of the coefficient of hydraulic resistance for flows of the considered class. Typical dependencies of the pressure at the control point for the basic configuration of the pipeline and in the presence of a check valve in the system are demonstrated. The result obtained in this work summarizes the previous data of the authors regarding the possibility of using the applied approach to solve a broad class of problems related to unsteady fluid flows in pipelines.
KEY WORDS
unsteady liquid flows, pipeline hydraulic systems, numerical modeling, pump start