Amgad Elansary

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 …

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.

In this paper, the problem of optimal rehabilitation of water distribution networks (WDNs) for both steady and transient state is investigated. Two objectives are considered in this study: minimizing rehabilitation cost by considering pipe size diameters as decision variables and minimizing the transient impacts by minimizing a surge damage potential factor (SDPF). A multi-objective ant colony optimization (MOACO) model is developed to solve this problem. The developed model is verified using the well-known New York City tunnel network. The application is carried out to modify an existing real WDN in New Cairo district designed in steady-state conditions to cope with the transient condition. The advantage of this study is to produce a set of solutions that help decision makers to identify the suitable approach, while evaluating and aggregating the preferences over multiple objective functions.

This paper addresses the problem of minimization of leakage in water distribution networks through the introduction and regulation of Flow Control Valves'FCVs". This problem is formulated as two objectives problem and is solved using multi-objective genetic algorithm. The first objective is to minimize the number of valves" a surrogate for installation valves cost" and the second one is represented by the minimization of the total leakage in the system while achieving the required pressure constraint at each node. The great advantage of mis study is that, in one run, several trade-off optimal solutions are obtained with a different level of compromise between the conflicting two objectives. Each solution from these optimal ones consists of: minimum number of FCVs, the best locations for the obtained number of valves and optimum valves settings, not only at one time period, but at each time period through the day …

Air vessels are widely used in water distribution system to protect from pump power failure. The process of sizing air vessels is very important in obtaining the the most economical vessel size and correct size of inlet/out/outlet pipe diameters that will protect the pipe system. This paper presents the developed model TRANSNETP that is used in analyzing transient flow due to pump power failure in pipe network system using air vessel as a protection device and also determining the optimal volume and optimal inlet/outlet pipe diameter for air vessel

Two mathematical formulations for the computation of transient flow in piping systems are compared with experimental data. The formulations are: a four-equations fluid structure interaction model (FSI) that includes Poisson coupling, and a two-equations model for the fluid. Both models are solved numericaly using the method of characteristics. A partial-closure of a valve located at an intermediate point in a pipeline is used to create transient flow. The two-equations model computed the maximum pressure peak satisfactorily but the FSI model gave an overall better simulation. An unsteady-friction model, added to the FSI model, did not influence the final results significantly. The experimental procedures followed to obtain the valve characteristics and the pressure history along the pipeline are explained in detail. Excellent numerical results at the valve are obtained when experimental data is used to simulate the time …

The fundamental problem addressed during this study lies in the poor quality of surface water in Gharbia Main drain (Kitchener drain). This drain receives agricultural, domestic, industrial, as well as solid wastes from villages and cities located around its path. The main objective of this research is to manage water quality at the drain. The service area of the drain was divided into 6 main basins in order to facilitate the identification of the critical basins along the drain. Water samples were collected from the drain at each basin, and analyzed for different parameters by three different certified laboratories. The parameters included chemical oxygen demand (COD), total suspended solids (TSS), total nitrogen (TN), and total phosphorus (TP). The concentrations of the selected parameters were also obtained from the literature data. Data analysis was conducted using the box plot tool in order to identify the most reliable data to be used as a benchmark for comparison with the modeling data. A tailored water quality modeling was created using MATLAB to simulate pollutant transport in Gharbia Main drains. Exponential and mass balance equations were used to estimate the targeted water quality parameters along the drain path. Model validation was performed between model estimation and actual data. From an economic point of view, it is recommended to apply the depollution projects in the most critical basins. Thus, a comparison was conducted between the current situation and three proposed scenarios of improving water quality at most critical basins through reducing the load of the domestic wastewater. The model results showed that basins No. 1 …

This paper introduces an approach for solving coupled flow and transports equations in a variable density flow system and presents a numerical model for pollutant transport and flow pattern in layered aquifer system. This formulation is general, flexible and capable of taking full advantage of the nature of flow in such multi-layer systems. Governing equations are discussed for the flow and solute solution with significant variations of density through a porous medium. Equations for mass conservation and solute conversation are formulated in terms of mass fraction hydraulic head and the mass fraction concentrated solute solution. These equations are combined into two nonlinear-coupled partial differential equations. The non-linearity arising from the density variation and from a velocity dependent dispersion tensor made the problem very hard. Therefore, special techniques including mixed interpolation finite …

The control of stresses and liquid pressure surges in pipes is an important problem in the design of hydraulic pipe networks. The method of characteristics has been used to solve the transient stresses and pressures in liquid-filled piping systems. The friction force is included in the equations of motion for the fluid and the pipe wall. The maximum pressure and maximum stress at any point along the length of the pipe are evaluated for the entire simulation time. A nonlinear search technique has been developed using the simplex method. The optimal valve closure is sought, that will minimize the maximum pressure and/or stresses. A continuous optimal valve closure policy is specified using spline functions. Numerical examples are presented showing the reduction of the dynamic pressure and the dynamic stress from linear valve closure to optimal valve closure for a simple pipeline and a complex pipeline. Also, a method for choosing the shortest time of closure which will keep the stresses below specified allowable stresses is presented.

The control of stresses and liquid pressure surges in pipes is an important problem in the design of hydraulic pipe networks. The method of characteristics has been used to solve the transient stresses and pressures in liquid-filled piping systems. The friction force is included in the equation of motion for the fluid and the pipe wall. The maximum pressure and maximum stress at any point along the length of the pipe are evaluated for the entire simulation time. The Von Mises criterion is used for the stress calculation. A nonlinear search technique has been developed using the simplex method. The optimal valve closure is sought, that will minimize the maximum pressure and/or stresses. A continuous optimal valve closure policy is specified using spline functions. Numerical examples are presented showing the reduction of the dynamic stress and the dynamic pressure from linear valve closure to optimal valve closure.

The control of axial stresses and liquid pressure surges in pipes is an important problem in the design of hydraulic pipe networks. The method of characteristics has been used to solve the transient stresses and pressures in liquid-filled piping systems. Friction is included in the equation of motion. The HZim pressure and maximum stress at any point along the length of the pipe are evaluated for the entire simulation tine. A nonlinear search technique has been developed using the simplex method. The optimal valve closure is sought, that will minimize the maximum pressure and/or stresses. A continuous optimal valve closure policy is specified using spline functions. Numerical examples are presented showing the reduction of the dynamic stress and the dynamic pressure from linear valve closure to optimal valve closure.

A numerical method to calculate the load-settlement of an axially loaded pile is presented. The method is based on an iterative scheme that tests the global equilibrium conditions and the load transfer (t-z) equations. The scheme is both accurate and computationally very economical.