Water Hammer Phenomenon Research Articles

Dynamic analysis and shape sensing of pipes subjected to water hammer by the inverse finite element method

Pipe structures are commonly employed in modern industries. However, the transient pressure induced by water hammer leads to a high risk of structural damage, highlighting the importance of Structural Health Monitoring (SHM). The inverse Finite Element Method (iFEM) offers a way to reverse structural deformations based on a set of discrete strain data. In this paper, the water hammer phenomenon in a Reservoir-Pipe-Valve (RPV) system is investigated. The element iQS4 is adopted to reconstruct dynamic deformations for the pipe using iFEM. The water hammer resulting from an instantaneous closure of the valve can generate significant fluid pressure, leading to severe pipe vibrations. The vibration deformations can be monitored by iFEM. The maximum error of the pipe nodal displacement is below 3 % and the average error is below 2 % in the proposed several sensor location cases, even the mesh of iFEM is coarser than the FE model. Among the sparse sensor location cases, the X path which is suitable for Fiber Bragg Grating (FBG) sensors has the highest accuracy of the displacement reconstruction. The results reveal a promising prospect in the real-time monitoring based on iFEM for pipes.

Numerical modeling and simulation of water hammer phenomena using the MacCormack method

ABSTRACT Water hammer refers to pressure fluctuations caused by changes in fluid speed in hydraulic systems. This research proposes a model using the MacCormack method to study and control water hammer, specifically focusing on managing valve closure to reduce shock wave pressure during transient flow. Numerical simulations compare linear and quadratic closure laws for both rapid and gradual valve closure, with the goal of identifying the optimal laws. The findings show that with faster closure times, the overpressure at the valve section decreases linearly in the second quarter of the return period (t4). The application of the quadratic law results in reduced pressures at the valve compared to the linear law, with a maximum pressure difference of 0.05 bar between the highest and lowest values. When searching for the optimal valve closure law to mitigate overpressure, it is found that the exponent ‘m’ falls within the range of 1.117–1.599. As the slow closing time increases gradually, the range of variation for ‘m’ decreases. Furthermore, in the case of underpressure prevention, the exponent ‘m’ ranges from 0.95 to 1.419, and the range of ‘m’ remains relatively constant with the increase in closing time.

Modeling of low Mach number unsteady turbulent pipe flows

AbstractUnder adiabatic conditions, and neglecting temperature variations due to entropy production, we present a set of Reynolds Averaged Navier–Stokes (RANS) equations for fluids of low compressibility, i.e., fluids in the liquid state. In the low Mach number limit, we specialize the RANS equations to the one-dimensional unsteady pipe flow, and we deduce the dimensionless number that plays a predominant role in the flow behavior. We reduce the system of equations to a linear damped wave equation, and use its analytical solution to investigate the propagation of large amplitude pressure waves in liquid-filled pipes (water hammer phenomenon). We test the model reliability by comparing the analytical solution of the proposed model against experimental data available in the literature.

Method to determine instantaneous transient responses in pressurized pipes from transfer functions and state space for evaluation of leak signals

This article addresses the impact of transient pressure anomalies in hydraulic systems, triggered by the opening or closing of valves or pumps, instantly disturbing the line of hydraulic gradient (LGH). This variation in pressure has significant consequences both in hydraulic and structural terms for water networks. Most of the existing techniques to detect transients in water distribution systems use asynchronous methods, generating timeless information that limits the response capacity in critical situations. Therefore, an automatic transient detection system based on the Internet of Things (IoT) is proposed, capable of identifying overpressure or underpressure pulses in soft real-time, activating alarms to facilitate decision-making. This approach helps maintain the safety of the water distribution system and prevent leaks in the network. Furthermore, a model of the transient behavior of pressure and flow is presented by linearizing the water hammer equations from the Laplace transform, thus generating a transfer function that describes the algebraic relationship between the outlet and inlet of the hydraulic system.•The transient analysis of the hydraulic system prototype underscores its high sensitivity to initial conditions, attributed to turbulence. This observation suggests the possible presence of a dynamic strange attractor related to water hammer phenomena in pressure pipes.•The methodology involving transfer functions and state-space models enables the assessment of how leaks impact the transient responses of the system, including the magnitude, duration, and frequency of disturbances generated by them.•The proposed method introduces a dynamic transfer function capable of identifying instantaneous changes over time in terms of flow and pressure.

Water hammer mitigation by internal rubber hose

The aim of this research was to experimentally analyse the possibility of using a rubber hose placed inside a pipeline to mitigate the water hammer phenomenon. The experiments were conducted using a steel pipeline with an inner diameter of 53 mm and an EPDM rubber hose with a diameter of 6 mm. Hydraulic transients were induced by a rapid closure of the valve located at the downstream end of the pipeline system. In order to analyse the influence of steady-state flow conditions on the maximum pressure increase, measurements were carried out for different values of initial pressure and discharge. The experimental results indicate that placing a rubber hose inside a pipeline can substantially attenuate valve-induced pressure oscillations. It was observed that the initial pressure has a significant influence on the capacity of the rubber hose to dampen the water hammer phenomenon. Comparative numerical calculations were performed using the Brunone–Vitkovský instant acceleration-based model of unsteady friction. It was demonstrated that this approach does not allow satisfactory reproduction of the observed pressure oscillations due to the viscoelastic properties of the EPDM hose used in the tests.

Hydrodynamic Analysis Of Water Hammer Phenomena In Hydropower Stations Under Turbine Extreme Operating Conditions

This research article investigates transient hydraulic effects, particularly water hammer phenomena, in a hydropower plant (HEPP) through a comprehensive mathematical model and simulation analysis. Utilizing methods of characteristics and FORTRAN programming, the study develops a model that incorporates water hammer considerations, including friction, in the water conveyance system of the HEPP. The system layout encompasses an upstream reservoir, penstock, turbine unit, and downstream reservoir. The research explores the influence of guide vane closure and pressure regulating valve (PRV) opening and closing laws on pressure variations, mass oscillations, and water level fluctuations within the system. Numerical results indicate that PRV failure may not significantly impact turbine speed, but it results in excessive pressure oscillations in the spiral casing head, exceeding allowable pressure control values. The study identifies a critical PRV diameter of 0.6m, causing a maximum pressure in the spiral case of 370m, surpassing the acceptable limit of 250m, with a speed rise rate exceeding 50%. Conversely, a PRV diameter greater than or equal to 0.9m leads to unnecessary water energy loss. The findings emphasize the importance of carefully selecting PRV parameters to optimize system stability and efficiency. The study's comprehensive analysis provides valuable insights into the interplay of various parameters, contributing to a scientific basis for optimizing operational parameters and ensuring reliable and efficient hydropower plant performance.
 

Conceptual analogy between the water hammer phenomenon in free-surface and pressurized-pipe flows

ABSTRACT The water hammer phenomenon, commonly acknowledged in pressurized pipe-flows is relevant to various water distribution systems. This phenomenon constitutes a major concern for hydraulic researchers and designer, given the dramatic consequences of this phenomenon on hydraulic structures and human life. This study aimed at expanding research on the water hammer waves in the free-surface flow framework. The main objective was to address a comprehensive simulation of the free-surface wave behavior caused by the abrupt closure of sluice-gate in prismatic open channel. The one-dimensional Saint-Venant equations embedding the Boussinesq add-on was used to predict the free-surface wave behavior; which was discretized using the (2–4)-dissipative scheme. Results evidenced the analogy between the water hammer wave behavior in free-surface and pressurized pipe flows. Furthermore, results illustrated that the water hammer maneuver produced a sudden depth rise, about three times of the normal depth value in the cross section adjacent to the gate. From a computational point of view, the proposed solver provided simplicity and accuracy attributes in simulating shock-waves in free-surface-flow. This solver also consumed low computational time compared with the conventional or multiple grid technique – based Finite Element Algorithm.

Research on pressure wave decoupling method for the nozzle of common rail electronically controlled injector based on water hammer theory

The pressure fluctuation in nozzle of the common rail injector directly affects the stability of fuel injection. As the pressure fluctuation often the result of coaction of multiple factors, it is difficult to carry out in-depth research. To reveal the mechanism of pressure fluctuation of common rail injector nozzle, based on the verified AMESim simulation model of the injector, the decoupling method of pressure wave in delivery chamber of the injector was investigated by applying the water hammer theory. The water hammer pressure in delivery chamber was divided into four stages, and pressure waves caused by the needle valve opening can be decoupled from that caused by the needle valve closing. In the range of 80–180 MPa rail pressure, both the opening and closing processes of the needle valve are direct water hammer phenomena. It is found that the water hammer pressure of the delivery chamber caused by fuel injection mainly consists of three pressure waves through a series of analysis and simplification. The results show that, all the pressures obtained by the superposition of three pressure waves under different working conditions are in good agreement with the simulated water hammer pressures.

Experimental research on vortex-induced vibration suppression of pipeline intelligent plugging operation

Pipeline maintenance technology based on smart isolation device (SID) is an important method to prevent failure accidents for subsea oil and gas pipelines. However, during the plugging operation, vortex-induced vibration may occur due to the complex changes of flow field, which can affect the plugging stability. To ensure the safety of plugging operation, it is necessary to reduce the vortex-induced vibration caused by pipeline plugging. In this paper, an experimental investigation on vortex-induced vibration suppression for subsea pipeline plugging operation is conducted from three aspects. The shape of end face, plugging velocity and spoiler device are investigated to suppress the vortex-induced vibration response. The results demonstrate that the vibration suppression effect of end faces with hemispherical shape is the best compared with the footstep shape and parabolic shape. For the plugging velocity, high-velocity plugging can induce stronger water hammer phenomenon, leading to destructive vibration of pipelines. In addition, the active spoiler device with two relative spoilers achieves the best vibration suppression effect, and the average fluctuation rate has decreased by 7.6%. The experimental research can ensure the safety of plugging operation, which is beneficial for preventing pipeline failure.

New Advances in Water Hammer Problems

When the flow within pressurized pipes experiences abrupt stoppages, initiation, or directional alteration, it gives rise to the phenomenon of water hammer, characterized by the propagation of waves [...]

Modeling of Pipe Whip Phenomenon Induced by Fast Transients Based on Fluid–Structure Interaction Method Using a Coupled 1D/3D Modeling Approach

The sudden increase in the operating pressure of nuclear power plants (NPPs) is due to the water hammer phenomenon, which tends to produce a whipping effect that causes serious damage to the pipes and their surroundings. The mechanical response of these pipelines under the influence of such fast fluid transients can be estimated using the fluid–structure interaction (FSI) method. The computational time and expense are predominantly dependent on the number of finite elements developed in the model. Hence, an effective modeling technique with limited and efficient nodes and elements is desired to obtain the closest possible results. A coupled 1D/3D finite element modeling approach using the FSI method is proposed to determine the influence of fast transients on the mechanical pipe whipping behavior of gas pipelines in NPPs. The geometric coupled modeling approach utilizes the presence of both the 3D solid elements and the 1D beam elements sharing a local conjunction. The computational model is modelled for a pipe-to-wall impact test scenario taken from the previously conducted French Commissariat a l’Energie Atomique (CEA) pipe whip experiments. The results of displacement, stresses, and impact velocity at the 3D section featuring the elbow are compared for the change in the 3D solid length varied at the juncture of the elbow. The computed results from the Ansys FSI coupling method using the Fluent and Transient Structural modules provides fair validation with the previously conducted experimental results and correlates with the CEA pipe whip tests on pipe-to-wall impact models. Thus, the 1D/3D coupled modeling approach, which minimizes the area of the solid region by constricting it to the impact area with appropriate contact modeling at the junctures, can be considered in the future for decreasing the computational time and the creation of finite elements.

Pressure-Transient Behavior of Vertical Wells Considering Dynamic Water Hammer and Dynamic Induced Fracture: Theory and Case Studies.

Water injection can result in the creation of induced fracture by connecting natural fractures. The induced fracture penetrates the entire reservoir, leading to the interconnection of injection and production wells and ultimately resulting in water breakthrough and the abandonment of production wells. During well work, the induced fracture exhibits dynamic behavior characterized by extension and closure, known as the dynamic-induced fracture phenomena. During the shut-in process, fracture closure phenomena are often accompanied by water hammer phenomena, which can be detected bottom hole pressure data. However, numerical simulation methods are difficult to describe their dynamic processes. Therefore, we urgently need a mathematical model to fill this gap. In this work, we developed a waterflooding-induced dynamic fracture (WIDF) model. Dynamic water hammer phenomena, multi-dynamic closure phenomena, and fracture storage phenomena are introduced into the WIDF model to describe the induced fracture dynamic behavior. Field cases demonstrate that the WIDF model can improve the accuracy of interpreted parameters and correct incorrect model selection. Green function and Newman product method are used to characterize single-phase water flows within tight reservoirs. Then, the induced fracture is discrete into N segments through the boundary element method. Discrete-induced fractures are divided into n parts. Based on the induced fracture bending property, conductivity variation is independent in each part. The feature line method is used to solve the pressure response of the dynamic water hammer. The Duhamel principle is applied to couple the storage effects and reservoir pressure response. The Laplace transform method transforms the model into Laplace space so that it can be solved easily, and the Stehfest numerical inversion method transforms the model into real space to obtain the final solution. Our results show that the dynamic water hammer flow (DWH) regime with an oscillation curve and the multi-dynamic closure flow (MDCF) regime with peaks exist on the type curve. Resistance coefficient (f) and inertia coefficient (I) control the DWH regime. Fracture storage coefficient (Cf), dynamic fracture closure rates (Delpatm), and induced fracture closure half-lengths (xdfm) control the MDCF regime. It is worth noting that the peak position can be adjusted by the Delpatm and xdfm parameters, achieving a more accurate match to the field cases. The Cf is identified, which corrected for the amplified wellbore storage coefficient. Obtained permeability is also in a reasonable range of permeability for tight reservoirs. In summary, a series of mathematical methods are used to develop and solve an injection well model to identify the dynamic behavior of the induced fracture. Numerical simulation methods are used to verify the accuracy of the WIDF model. Two field cases from X Oilfield demonstrate the practicability of the WIDF model. Dynamic identification of the induced fracture would help engineers develop appropriate injection schemes to prevent water breakthroughs.

Water Hammer Arresters; Review Studies and Practical Experiments for Alternatives

The current research deals with practical studies that explain to the Iraqi consumer multiple instances about the phenomenon of water hammer which occur in the water pipeline operating with pressure. It concern a practical study of the characteristics of this phenomenon and economically harmful to the consumer the same time. Multiple pipe fittings are used aimed to reduce this phenomenon and its work as alternatives to the manufactured arresters that used to avoid water hammer in the sanitary installations, while the consumer did not have any knowledge as to the non-traded for many reasons, including the water pressure decreases in the networks and the use of consumer pumps to draw water directly from the network. Study found a number of conclusions and recommendations of some of the most important pipe fittings have been effective in curbing this phenomenon, as reflected in the illustrations included in the search.

Analysis of the Cause of Gas Pipeline Burst in a Gas Production Plant

In order to reduce the failure of pipes, the macroscopic morphology, macroscopic crack, chemical composition, hardness, microstructure and so on were tested through the macroscopic analysis, physical and chemical property inspection, hydrogen-induced cracking test and sulfide stress cracking test. The SEM was used to analyze the microscopic cracks, fractures and element distribution at the failure site. The results show that the cracking zone of the failed pipe section has the characteristics of bulging deformation and thinning of wall thickness. The macroscopic fracture of the fracture is a typical 45° shear shape. The fracture was observed under the high magnification of scanning electron microscope and showed dimple morphology. The failure mode of the failed pipe segment is plastic fracture. The reason for the failure of this pipe is the special geographical location of this section of the pipeline, and the sudden increase of pipeline pressure after the well opening operation causes the water hammer phenomenon, which causes the local bulging of the pipe body, which further leads to burst failure.

Developments in analytical wall shear stress modelling for water hammer phenomena

New developments in analytical modelling of wall shear stresses during water hammer events are presented and discussed in this paper. These include further development of models based on the quasi-steady and unsteady hypothesis of hydraulic resistances. All the analyzed solutions have been improved so that they have extended ranges of applicability and the simplest possible mathematical form. Exemplary comparative studies were carried out, which showed their advantages and disadvantages. Explicit analytical formulas of wall shear stress were derived for the first time. They will be particularly useful at the stage of design and modernization of the pressurized piping systems (water supply, oil-hydraulics etc.) and enable effective analysis of leakages and other damages (ruptures, fatigue related failures) occurring in industrial pipeline systems. With their help, it will be easier to prevent the increased pulsating pressures occurring during water hammer events (protect against failures), and to verify numerical models used for years in simulations of transient pipe flows.

Water Hammer Analysis in Water Pipelines and Methods for Protection

In water processing industry, pressurised pipeline problems bring dangerous consequences, causing flooding, traffic accidents or death, financial and material losses and the disruption of the water supply. There are some problems in water pressurised pipelines system occur gradually, and some problems occur in very sudden without any warning with massive impacts and harms. Most of the sudden events that affect water system and municipal operation and maintenance centres are the phenomenon of sudden explosions and cracks in water pipes which lead to disaster. The phenomenon of water hammer is as a result of imperfect design or poor operation methods. The transition in the pressurised pipeline from one steady state to another steady state such as from a constant velocity to another velocity without a protection system make huge in pressure change. Any change in velocity leads to a pressure changes in very short time will cause to disaster strikes for the system stabilization. Professional design of liquid pipelines and proper selection of materials prevents the phenomenon of water hammer. Therefore, in this paper, the important issues on water hammer, protection systems and professional planning with special software programmes such as Allievi software was addressed.

UNSTEADY FLUID FLOW IN PRESSURISED CLOSED PIPES IN EXPERIMENTAL BENCH EXAMPLES

The paper indicates the frequent occurrence of transient states in hydraulic systems. Particular attention was paid to the phenomenon of water hammer – the causes and effects of this phenomenon. A complete analytical description of this phenomenon has not yet been developed. New theoretical models are still being developed and need to be verified experimentally. The paper focuses on presenting the development of experimental stands for the study of water hammer in hydraulic pipes. Subsequent modifications of the experimental stands for the speed of the shut-off valves and their tightness, as well as for the minimisation of the occurrence of the effects of the pulsation of the performance of the pump supplying the line under investigation, are presented. The stand presented as the final one also allows the testing of transients in hydraulic lines for various types of working fluid (oil, emulsion, distilled water).

Analysis of the harmfulness of the water hammer phenomenon in high density poly-ethylene (HDPE) pipes

In this numerical study, the three-dimensional finite-element method is used to analyze the degree of harmfulness of the water hammer phenomenon in high-density polyethylene (HDPE) pipes damaged by cracking. The fracture criterion used in this study is the integral J, which was calculated in semi-elliptical cracks in four different positions. The effect of the flow rate and crack configuration on the J-integral is analyses. The pipe section was constructed simulating a commercially available model. A 3D finite-element analysis was performed in Warp Software. All materials used in the models were considered to be isotropic, homogeneous, and linearly elastic. The results obtained show that an increase in pressure caused by the water hammer phenomenon leads to a remarkable increase in the J-integral. It is also shown that an internal longitudinal crack in a pipe is the most dangerous. It can also be seen that an increase in the flow velocity leads to an increase in the J-integral.

Uji Eksperimental Fenomena Water Hammer dengan Variasi Ketinggian Surge Tower

In this study an analysis of the water hammer process was carried out in a piping installation with two pumps of different specifications arranged in a single arrangement. The solution given as a form of water hammer protection is variations in the height of the surge tower in piping installations. The aim of this research is to identify the phenomenon of water hammer in piping installations with different pump discharges and the effect of the height of the surge tower as a damper against pressure fluctuations that occur. The test is carried out by closing the valve suddenly and varying the height of the surge tower to determine the pressure value that occurs due to the water hammer effect. From the experimental test results, it can be seen that a surge tower with a height of 1 meter can best dampen back pressure due to the water hammer effect at a discharge of 2.4 m3/h. The theoretical and experimental analysis shows that the addition of a surge tower can reduce the pressure due to the water hammer effect. The pressure drop is 2.6 kg/cm2 to 2.2 kg/cm2 in pump installation 1 and the pressure drop is from 4.6 kg/cm2 to 1.8 kg/cm2 in pump installation 2. The use of a surge tower with a height of 1 meter can best reduce back pressure with 2.78 hours s at a discharge of 1.4 m3/h.

Development of Smoothed Particle Hydrodynamics based water hammer model for water distribution systems

ABSTRACTSmoothed Particle Hydrodynamics (SPH) method is used to solve water hammer equations for pipeline systems due to its potential advantages of easily capturing column separation and slug impact. Currently, the SPH-based water hammer model has been only developed to simulate single pipe flow with simple boundary conditions. It is still a challenge to apply the SPH-based water hammer model to practical water distribution systems (WDSs). To address this issue, this study develops a complete SPH-based Water Hammer model for Water Distribution System (SPH-WHWDS). Within the proposed method, the complex internal and external boundary condition treatment models of the multi-pipe joint junction and different hydraulic components are developed. Buffer and mirror particles are designed for boundary treatment coupling with the method of characteristics (MOC). Two benchmark test cases, including an unsteady pipe flow experiment and a complex WDS, are used to validate the proposed model, with the data from the experimental test in the literature and the simulation results by the classical MOC. The results show the proposed SPH-WHWDS model is capable to simulate transient flows with accurate and robust results for pipeline systems, which may provide further insights and an alternative tool to study water hammer phenomena in complex WDSs.