Investigation on Maximum Upsurge and Air Pressure of Air Cushion Surge Chamber in Hydropower Stations

Abstract

The maximum upsurge (MU) and the maximum air chamber pressure (MACP) are critical parameters for the design of air cushion surge chamber (ACSC) in hydropower stations. In this paper, the existence of the MU and the MACP are proved under compound conditions. The theoretical formula predicting the most dangerous superposition moment of the MU and the MACP under compound condition is derived, and the influence factors are analyzed as well. To verify the accuracy of the formula, the rigid model based on Runge-Kutta method (RKM) and the elastic model based on the method of characteristics (MOC) are established, respectively, according to the parameters of the ACSC system in the practical hydropower station. The numerical results agree well with the theoretical predictions. In addition, the MU and the MACP under three control conditions are simulated, respectively, and the results show that when the cross-sectional area of throttled orifice is small, the MU and the MACP occur under the successive load rejection condition (SLR); when the cross-sectional area is large, the MU and the MACP occur under the load rejection after load acceptance condition (LRLA).

Effects of Surge Tank Geometry on the Water Hammer Phenomenon: Numerical Investigation

“…The Method Of Characteristics (MOC) has been widely applied to simulate the transient flow for various situations: water pipeline (Zhang et al, 2018;Bettaieb and Taieb, 2020), power plant (Guo et. al., 2017;Liu et al, 2017), and water pump station (; Kim et al, 2014;Hur et al, 2017).…”

“…Overall, water hammer takes place in various hydraulic systems such as pump stations (Wan and Huang, 2011;Hur et al, 2017;Kim et al, 2014;Rohani and Afshar, 2010), hydro-power systems (Guo et. al., 2017;Liu et al, 2017;Riasi and Tazraei, 2017), water-transferring systems (Duan et al, 2010;Kim, 2010;Collins et al, 2012;Zhang et al, 2018;Bettaieb and Taieb, 2020), and oil-transferring systems (Behbahani-Nejad and Bagheri, 2010;Esmaeilzadeh et al, 2009). Water hammer causes damages in different ways (i) severe fluctuations in pressure and noise, (ii) cavitation occurrence in the hydraulic systems.…”

Research on Multi-Objective Optimization to the Shape of Air Cushion Surge Tank

“…Restricted by terrain, in these hydropower stations, the tower type surge chamber built close to the plant has a large amount of engineering, while the well type surge chamber built far away from the plant in the rock mass is difficult to ensure the regulation effect [1]. Air cushion surge tank (ACST) is a pressure regulating device with a closed top and provides compressed air above the water surface in the chamber, which can effectively suppress surge amplitude and reduce the height of the surge chamber [2]. Building ACST in thick rock layer can make full use of rock resistance to reduce project cost.…”

“…The main innovations are as follows. ( 1) The numerical simulation model of the hydropower station with ACST is established; (2) The influence of structural parameters of ACST on the transient process of hydropower station is analyzed; (3) A multi-objective optimization decision-making framework for the shape of the surge tank was established and recommendations for the shape optimization are given.…”

Water Hammer Control Analysis of an Intelligent Surge Tank with Spring Self-Adaptive Auxiliary Control System

“…It usually occurs with a valve shutdown and opening, a pump accident and start-up, or even a sudden depressurization of a pipeline system. The water hammer is common in pump rise systems [2][3][4][5], hydroelectric station systems [6][7][8], hydraulic conveying systems [9][10][11][12], and even in oil conveying fields [13,14] and so on. Unfortunately, water hammers can cause severe pressure and flow oscillations, along with cavitation, noise, and other hazards.…”