Fluid-Structure Interaction in a Pipeline Embedded in Concrete During Water Hammer

Abstract

Pipe vibration induced by water hammer frequently emerges in water conveyance system, especially in the hydropower plant or pumped storage power station with long diversion pipelines. This vibration in turn affects the hydraulic pulsation so that undesired fluid-structure interaction (FSI) arises. In this research, attention is given to a pipeline embedded in concrete. A six-equation model was derived to describe the fluid-pipe-concrete interaction considering Poisson coupling and junction coupling. With the elastic and homogeneous hypotheses, an iterative approach was proposed to solve this model, and the results were validated by experiment and classical water-hammer theory. Then dynamic FSI responses to water hammer were studied in a reservoir-pipe-valve physical system. Hydraulic pressure, pipe wall stress and axial motion were discussed with respect to different parameters of concrete. Results obtained by the two-equation model, four-equation model and six-equation model show characteristics of pressure wave and stress wave separately with and without FSI.

Modeling of Pipe Whip Phenomenon Induced by Fast Transients Based on Fluid–Structure Interaction Method Using a Coupled 1D/3D Modeling Approach

“…where ρ f and A f are the density and area of the fluid inside the pipe, with x being the flow direction of the fluid with respect to time t, and P is the pressure of the fluid in the center [35]. The computational fluid dynamics (CFD) analysis in the Ansys Fluent module is solved for three-dimensional flow model under the action of the inlet pressure surge at the initial instance.…”

“…where w x is the axial displacement of the pipe wall due to the motion of the fluid, with σ x being the pipe stress along the direction [35]. The dynamic and kinematic continuity at the interface is attained through the following Equation ( 8) (dynamic continuity) and Equation ( 9) (kinematic continuity):…”

Analysis of Water Hammer and Pipeline Vibration Characteristics of Submarine Local Hydraulic System

“…Liu [5,6] used a genetic algorithm to optimize the valve closure law for controlling the maximum peak pressure of the water hammer and trained a specific system valve closure law prediction model through the radial neural network based on a large amount of data. Chen [7] studied the dynamic structure interaction responses to water hammer in a reservoir-pipe-valve physical system and discussed hydraulic pressure, pipe wall stress, and axial motion concerning different parameters. Afshar [8] proposed an implicit method of characteristics to solve problems of transient flow caused by the closure of a valve and failure of a pump system, which alleviates the shortcomings and limitations of the most commonly used conventional MOC.…”