Investigation on method of characteristics and semi-implicit method for pressure linked equations algorithms for water hammer based on unsteady friction

Abstract

The misoperation of hydraulic components such as pumps and valves in pressurized pipelines triggers water hammer phenomena and seriously threats the safe operation of hydraulic systems. At present, the main water hammer simulation methods are method of characteristics (MOC), and further investigation of new algorithms is needed. Therefore, a new method for simulating the water hammer using the finite volume method (FVM), semi-implicit method for pressure linked equations (SIMPLE) algorithm is proposed in the present work. Compared with the experimental data, the accuracy and reliability of the proposed algorithm are verified. Results show that the IAB, MIAB friction models not only predict the first pressure peak but also accurately predict the pressure attenuation. From the comparison of the MOC, SIMPLE algorithms, the results of the two algorithms are almost the same in front of the valve, while near the upstream tank, when using the same friction model, the pressure attenuation predicted by the SIMPLE algorithm is slightly greater than that of the MOC method and closer to the experimental data. Therefore, the newly proposed algorithm can serve as an alternative to the MOC method in simulating water hammer. The investigation enriches the numerical methods of hydraulic transients and lays the foundation for subsequent program development.