Amgad Elansary

One of the objectives of this study was to reduce the undesirable dynamic pressure oscillation that occurs in a simple pipeline due to valve closure and to prevent the occurrence of column separation. This is accomplished by maximizing the minimum pressure in the pipeline. The second objective was to minimize the maximum dynamic pressure, and the third objective was to estimate the best (minimum) time of closure, T* c, that results in a pipe stress equal to the maximum allowable stress. The method of characteristics with the time-line interpolation technique was used to solve the transient stresses and pressures in a liquid-filled piping system. Frequency-dependent friction was used in the equation of motion for the fluid and the pipe wall. A nonlinear optimization technique was utilized to generate the optimum valve closure policy. Maximum and minimum pressure heads resulting from the optimal policy were …

One of the objectives of this study was to reduce the undesirable dynamic pressure oscillation in a simple pipeline due to valve closure and to prevent the occurence of column separation. The second objective was to minimize the maximum dynamic pressure and estimate the best (minimum) time of closure, T*, that results in a pipe stress equal to the maximum allowable stress. The method of characteristics with the time-line interpolation technique was used to solve the transient stresses and pressures in liquid-filled piping system. Frequency-dependent friction was used in the equation of motion for the fluid and the pipe wall. A non-linear optimization technique was utilized to generate the optimum valve closure policy. Maximum and minimum pressure heads resulting from the optimal policy were calculated and compared with those resulting from a uniform valve closure. Plots of the pressure variation at the valve for these two valve closure policies were also generated. Examples are presented to demonstrate the advantage of the optimum valve closure policy over the uniform valve closure policy. The reduction in the maximum dynamic pressure and stress at the valve for different Tc is also presented.

The Southern Valley Development Project (Toshka) is a major project located 1,000 km south of Cairo, Egypt. The project involves pouring Nile water out off Lake Naser into the desert in order to reclaim parts of it for agricultural use. The Toshka project is considered one of the largest projects in the world with its unique pumping station that delivers 25 x 106 m3/day (∼300 m3/sec). As a result, safety is a major concern and maximum protection measures against Waterhammer should be incorporated into the project's design. Waterhammer analysis will provide the required protection that is needed for both pump and pipeline. This paper contains numerical model that simulates pump power failure followed by a valve closure for a pumping system drawing liquid through a single pipeline and discharging it into a reservoir. The method of characteristics was used to solve the transient pressures in a liquid-filled piping …

The Southern Valley Development Project (Toshka) is a major project located 1,000 km south of Cairo, Egypt. The project involves pouring Nile water out off Lake Naser into the desert in order to reclaim parts of it for agricultural use. The Toshka project is considered one of the largest projects in the world with its unique pumping station that delivers 25 x 106 m3/day (∼300 m3/sec). As a result, safety is a major concern and maximum protection measures against waterhammer should be incorporated into the project's design. Waterhammer analysis will provide the required protection that is needed for both pump and pipeline. This paper contains numerical model that simulates pump power failure followed by a valve closure for a pumping system drawing liquid through a single pipeline and discharging it into a reservoir. The method of characteristics was used to solve the transient pressures in a liquid-filled piping …