Some aspects of physical and numerical modeling of water hammer in pipelines (original) (raw)

IAETSD-Design and Analysis of Water Hammer Effect in a Network of Pipelines.

There will be a chance for the destruction of the system due to transient if it is not provided with adequate protection devices. Generally, transient takes place when parameters involving in conventional flow are distorted with respect to the time. Rapid closing of valve in a pipe network will be resulting into hydraulic transient known as water hammer occurs due to sudden change in pressure and velocity of flow with respect to time. Due to impulsive action, pressure surges are induced in the system travel along the pipe network with the rapid fluid acceleration leading to the dramatic effects like pipe line failure, damage to the system etc. Considering the importance of hydraulic transient analysis, we design a system capable of verifying pipe network containing fluid flow.This paper demonstrates design of different pipe structures in pipe line network and analysis of various parameters like excess pressure distribution, velocity variations and water hammer amplitude with respect to time using COMSOL Multiphysics v 4.3. The magnitude of water transient in pipe line network at different pressure points has been discussed in detail.

MATHEMATICAL SIMULATION FOR TRANSIENT FLOW IN PIPES UNDER POTENTIAL WATER HAMMER

To protect the physical integrity of a pipeline system, there may be a need to install surge control devices, such as surge relief valves, surge tanks, or air-vacuum valves, at various points in the system. The main purpose of this study is to simulate the transient flow in pipes with water hammer using a mathematical modeling. By taking Omar Almokhtar Reservoir and Omar Almokhtar Grand Reservoir hydraulic system as a case study, where this system located at 35 Km south of Benghazi city. The analysis of simulation of this study is based on a characteristics method assisted by well known software called WANDA which was developed by Delft Hydraulics / Netherlands. Maximum and minimum pressures generated by the different scenarios implemented in this study confirm that the installed air vessels capacity of 1500 m 3 are sufficient to control all pressure values within the bar rating of the installed pipes. It is also found that the pipe section just upstream of OMG reservoir air valve(s) with adequate capacity is (are) needed at this section of the pipeline. Air vessels with capacity 1000 m 3 are not enough to damps the pressures that occur during transient duration.

Sensitivity Analysis for Water Hammer Problem in Pipelines

Iranica Journal of energy and environment, 2014

Water hammer is a transient flow in pipes that was created by sudden changes of velocity in pipe lines. This phenomenon can cause strong positive and negative pressures in water conveyance pipes and usually it poses pipeline to danger. Overall, water hammer creates by rapidly closing valves, shutting off or suddenly restarting pumps. It has destructive hydrodynamic effects in pressurized pipelines. In this study, governing equations of water hammer is numerically simulated using MATLAB software. Then, the sensitivity analysis in negative and positive pressures by changing some variables such as pipe diameter, pipe length and also wave velocity in pipe was investigated. Numerical simulation is based on characteristic method. Sensitivity analysis help designers to have well understand of water hammer phenomenon.

Model and protected design of water piping system to minimize the water hammer effect

Egyptian Journal of Chemistry, 2021

The effect of the water hammer is investigated to predict the water hammer effect in a wastewater pipeline and to develop the piping system design to overcome the predicted effect. The piping system is sensitive to any effects of the water hammer phenomenon. The sudden change in pressure within pipes or conduits used to transport liquid under pressure may result in serious damage. A modified numerical approach is developed to predict the water hammer effect. The system under study was modified to handle and reduce the effect of water hammer.By calculating the water hammer’s effect, the safe piping system design can be developed. A model was developed to predict the effect of water hammer and the expected pressure drop/increase across the piping system. The pipe properties and measured pressure are the model operating parameters. The maximum and minimum pressure envelopes across the piping system were calculated. By simulating the power failure and/or pump shut down, the model showed...

Investigation of Water Hammer Effect Through Pipeline System

— This paper we study the condition where the water hammer effect is occurs in pipe line. Water hammer can cause the pipe to break if the pressure is high enough. The experiment will be setup to investigate the water hammer effect in order to avoid the water hammer effect happen. The prevention of water hammer effect will be propose and prove the prevention method is successfully reduce the water hammer effect. The prevention method using is installing the bypass pipe with non-return valve. The experiment is done by capture the vibration signal by using data acquisition device and accelerometer. The pressure signal is capture after a sudden shutoff for the valve. The signal is than analyze and convert to wave speed. The project is differentiating and compares the water hammer phenomenon with different pipe material, pipe length, inlet diameter of pipe, and pressure in pipeline. From the experiment, result shown that the lower strength material pipe, smaller inlet diameter pipe, and longer pipe will deal with lager water hammer effect. Besides, the prevention method by installing by pass pipe with non-return valve of water hammer effect is proved successfully reduce the water hammer phenomenon by 33.33% of pressure.

Parameters affecting water hammer in metal pipelines

E3S Web of Conferences

The water hammer related to rapid wave pressure changes in hydraulic systems have been subjected to intensive research for more than a hundred years. Nevertheless, a large number of new papers appear each year. Current literature indicates model differences resulting from the used material of the pipe. In the hydraulic machinery, elastic (metal) pipes are usually used, while water transport in water supply system is currently realized with pipes whose deformation of the walls is viscoelastic. In this paper, the individual and group impact of all parameters influencing the results of numerical modelling of the water hammer occurring in the pipes will be analysed. The method of characteristics will be used to solve partial differential equations describing the flow.

Experimental Study of Water Hammer Pressure in a Commercial Pipe

Water hammer is a phenomenon caused by change in flow velocity and valve closing/opening time. It is undesirable. It causes because pressure transient in the pipe, vibration and noise. Excessive pressure causes pipe fracture by rupture. A review of literature has shown that earlier researchers concentrated more on the analysis of water hammer by method of characteristic while comparative study of method of water hammer analysis is insufficient. In the present study experimental and analytical analysis of water hammer pressure in a commercial pipe has been studied and analyzed. Method of characteristic (MOC), arithmetic method, theoretical method and experimental method are used in this thesis. In MOC, an element-wise definition is used for all the devices that may be used in a pipeline system and the corresponding equations are derived in an element-wise manner. The proper equations defining the behavior of each device including pipes are derived and assembled to form the final system of equations to be solved for the unknown nodal heads. Used method allows for any arbitrary combination of devices in the pipeline system. MOC was concluded it is superior to other methods. Keywords: flow control valve, pipeline system and valve closing time/valve opening time.

Water Hammer Analysis by Characteristic Method

American Journal of Engineering and Applied Sciences, 2008

Rapid changes in the velocity of fluid in closed conduits generate large pressure, which are transmitted through the system with the speed of sound. When the fluid medium is a liquid the pressure surges and related phenomena are described as water hammer. Water hammer is caused by normal operation of the system, such as valve opening or closure, pump starts and stoppages and by abnormal condition, such as power failure. Problem statement: Water hammer causes the additional pressure in water networks. This pressure maybe defects on pipes and connections. The likely effects of water hammer must be taken into account in the structural design of pipelines and in the design of operating procedures for pumps, valves, etc. Approach: The physical phenomena of water hammer and the mathematical model which provides the basis for design computations are described. Most water hammer analysis involves computer solution by the method of characteristics. In this study water hammer is modelled with this method and effect of valve opening and closure will be surveyed with a program that is used for this purpose and with a numerical example. Results: The more rapid the closure of the valve, the more rapid is the change in momentum and hence, greater is the additional pressure developed. Conclusions/Recommendations: For preventing of water hammer defects, is recommended that valves should be open or closed slowly. Also with using the method of characteristics, we can modelled all pipe networks, and see the affects of water hammer.

Investigating Water Hammer Problem in Piped Water Distribution System

IOSR Journal of Applied Physics, 2014

The water hammer in the form of disastrous surge pressure developed inside the piped water distribution system causes major damage. The one dimensional propagation of water surge pressure in a series of water pipes with varying diameter and angle has been studied theoretically. The numerical solution with different pipe materials for the pressure surge has also being evaluated. The sensible pressure due to surge varies significantly with pipe material and diameter but not much significantly with length and bending angle in a distribution layout.

The long term effect of hammer influenced in water pipe line (Case study: pipeline from Azadi to Hor

civil and project , 2023

Due to the increase in population as well as the increasing of the human need for water, it is vital for preserving water resource in each area. In the meantime, Iran has been in a state of inaccurate crisis due to the excessive withdrawal of water resources. Therefore, it is important to maintain water resources. And, the traditional methods of water transfer (using open channels and ...) are replaced by new methods such as the use of a water supply pipe. These methods, in addition to cost, have many technical benefits. Including increased transmission efficiency, reduced water waste, as well as saving passive defense principles. Meanwhile, the use of GRP pipes, in the last 40 years, has led to a dramatic increase. Although the life period of these pipes in the our country will reach 53 years, the efficiency of these engineering pipes has become more and more enriched, reaching its true position in the country. Due to the great efforts of the responsible and informed management of some manufacturers of these products in the country, the optimal use of this type of pipes is increasing. In this regard, Farassan Co., as the flagship of this industry, has made endless efforts to update and improve the quality of pipes, and has made significant progress. One of the most important points in the use of GRP pipes in comparison with other pipes is the lack of knowledge and awareness of some customers about these pipes and products, which is always a concern for employers and consultants. In this paper, in addition to the proper introduction of GRP Pipes and their use in comparison with other PIPES, it has been tried to discuss the control and monitoring the of the Water hammer in these types of products. In this regard, in the case of a water pipe line project from Azadi dam to the plain of Hor as one of the most important projects of water transportation in Iran, is briefly introduced and analyzed according to the details. Finally, a briefly studying about control and effect of the hammer phenomenon on the GRP pipes in special project is perfectly discussed.