The Influence of Boundary Conditions on Pressure Wave Reflection Simulation at Pipe

Abstract

In previous literature, the flow characteristics of pressure waves in hydraulic experiments have demonstrated that there are two types of reflected waves: the same pressure vibration trend type and the opposite vibration trend type, with the equal pressure amplitude as the original wave. The reflection characteristics in the simulation must be consistent with those in the experiment. To determine reasonable boundary conditions, this paper focused on the simulation of pressure waves reflection under five combinations of boundary conditions using the computational fluid dynamics (CFD) method. Three three-dimensional simulation models were developed based on the k-ε turbulence model. Reflection characteristics were obtained under different boundaries. The result shows that the pressure boundary in the pipe could get reflected waves correctly. Reservoir is considered more accurate than the pressure boundary, which can reflect the slight fluctuation of the reflected wave. Both the wall boundary and the velocity boundary could be used to simulate the operation of the valve. However, if intercepting a part of the pipeline as objective, the reflected wave shows phase advance and pressure amplitude attenuation compared with that at the same position in the original pipeline. This paper is helpful for setting reasonable boundaries in pressure wave simulation.