MATHEMATICAL MODELING FOR WATER HAMMER IN PIPE FLOW

Abstract

Water hammer phenomenon is a transient flow in pipes that was created by rapid changes of velocity in pipelines. This phenomenon can be caused strong positive and negative pressures in water pipelines. Overall, water hammer creates by suddenly closing valves, shutting off or suddenly restarting pumps. In this study, momentum (Euler) and continuity equations of water hammer is numerically simulated using MATLAB software. Sensitivity analysis has been investigated using several variables such as pipe diameter, wave’s velocity and friction factor. Method of characteristics (MOC) has been implemented in this study. Through the results obtained, it has been shown that when using pipe with diameter (1.2m) instead of (1m), the maximum pressure head decreased by 31.5%, and decreased by 47.7% in the case of using (1.4m) instead of (1m). In case of changing the values of friction factors, it has been shown that the maximum pressure head decreased by 0.86% when using the friction factor value (0.008) instead of (0.007), and decreased by 0.81% when using friction factor value (0.009) instead of (0.007). While for the effect of wave's velocity on the pressure head, it has been shown that the maximum pressure head increased by (10.6%) when using the wave's velocity (300 m/sec) instead of (250 m/sec) and increased by (19.13%) when using (350 m/sec) instead of (250 m/sec) and increased by (26.1%) when using (400 m/sec) instead of (250 m/sec). Also, it has been found that the ending section of pipe is the critical zone for water hammer.