Water Hammer Analysis Research Articles

Analysis of Water Hammer and Pipeline Vibration Characteristics of Submarine Local Hydraulic System

The hydraulic pipeline vibration noise is one of the main noise sources in submarine stealth conditions. Taking the local hydraulic system of a certain type of submarine as the research object, a model is first developed to simulate water hammer pressures and to study the influence of component parameters on the generation and transmission of water hammers. Then, using the maximum water hammer as the excitation, fluid–structure interaction (FSI) vibration characteristics analysis of the pipeline is carried out. Additionally, the simulation method of clamp bolt pre-tightening is discussed. Finally, the modal test of various specifications of the pipeline is carried out. The results show that the error between the simulation and the test results is within 10%, which verifies the correctness of the model settings. On this basis, with the position of the clamp as the independent variable and the maximum stress of pipelines as the dependent variable, the optimization of pipeline passive vibration control is carried out by genetic algorithm, and the finite element verification shows that the pipeline vibration stress is effectively reduced.

The first half-period of pressure heads for frequency response extraction and analysis of waterhammer with fluid–structure interaction

This paper details an efficient procedure to extract and analyze the pipe system characteristics from the pressure and stress waves generated during the first half-period of the water hammer with fluid–structure interaction (FSI). To this end, a new transient signal is generated using the first half-period of pressure heads through verified mathematical and numerical computations in the time domain. Then, the system’s resonant frequencies are extracted from the new transient signal by employing a fast Fourier transform (FFT) algorithm. The extraction procedure is verified using the analytical results from the literature. The analytical relations of the dominant resonant frequencies corresponding to the pressure and stress waves in the new transient signal are also derived to analyze the frequency data captured using the proposed approach. The effects of the stress wave (structural) frequencies are closely investigated, considering several hypothetical case studies. Both major FSI mechanisms during water hammer in a reservoir–pipe–valve​ system, namely Poisson and junction, are taken into account. The results demonstrate that the presented approach can manifest the hydraulic and structural properties of the pipeline system. The main stress wave frequencies result in a considerable increase in the amplitude of the extracted resonant frequencies, whereas a reduction effect is revealed due to the reflected stress wave frequencies. This research is of crucial importance for system identification in pipelines.

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.

Water Hammer Protection Measures and Calculation Analysis of Reservoir Water Pipelines

In fluid mechanics, the large pressure fluctuation caused by the rapid change of fluid flow in a closed pipeline is called water hammer. It has huge destructive power for pressurized water pipelines, which often lead to pipeline leakage or even burst. In this paper, through the analysis of the dynamic characteristics of the gas in the pressurized water pipeline, the necessity of setting the air valve is drawn. Then based on the Bentley HAMMER model, combined with the example of the reservoir water pipeline engineering, the water hammer analysis was carried out. Compared with the maximum pressure head before and after adding the air valve, it is reduced from 126.89 m to 62.11 m, a decrease of about 50%. At the same time, the negative pressure in the pipeline under transient conditions is also eliminated. The results show that the air valve used in the pressure water pipeline has a good effect on the prevention of water hammer.

RELAP5 application for water hammer analysis in different thermal-hydraulic systems

• Causes of water hammers: rapid valve operation, void-induced, condensation-induced. • RELAP5 code may represent water hammer due to valve operation and appearance of void. • The developed modelling recommendations are based on comparative analysis. • Water hammer in nuclear, fusion and district heating systems possible due to fast valve actions. • Integrity of pipelines in nuclear, fusion and district heating systems remain not violated. The water hammer phenomenon investigations employing RELAP5 code with one-dimensional two-fluid six-equation models of water and steam flow were performed and the main results shared in this paper. The capability of RELAP5 code to simulate transients leading strong pressure pulses was investigated employing the measurement results of three test facilities for different water hammer types: PPP at UMSICHT, CWHTF at FZR Dresden and PMK-2 at AEKI. Based on the benchmarking results the recommendations for the modelling of piping systems, which could be affected by different types of water hammer were developed and tested. The recommendations cover selection of thermal-hydraulic system conditions, parameters of modelling and RELAP5 code correlations. These recommendations have enabled to develop a detail RELAP5 models for the simulation of water hammer effects in further research works. The applications of RELAP5 code for water hammer analysis in different thermal-hydraulic systems (RBMK-1500 reactor main circulation loop, targets cooling/heating circuit in Wendelstein 7-X experimental stellarator facility and pipelines in district heating system) are presented in this paper. The performed analyses of transients demonstrated that the pressure pulsations could appear in all these systems as results of check valve closures. However, pressure surges are not so strong due to specific of such systems and integrity of pipelines remains not violated.

Analysis on water hammer protection of FPSO ballast water system

In practical engineering, the protection of FPSO water hammer is very important. Through simulation analysis, the relevant data are obtained to provide reference for relevant engineering practice. A general-purpose FPSO ballast water pipe network system was established by aft impulse software, and water hammer simulation calculation and analysis were carried out to find out the maximum pressure position of water hammer phenomenon. According to the water hammer generation mechanism, the simulation research was carried out by two-stage valve closing and adding surge tank into the pipeline. It was found that water hammer was easily caused by quick closing valve; the protection method of two-stage valve closing and installation of surge tank has a very objective protective effect, which provides a reference for related projects.

ConocoPhillips’ Water-Hammer Analysis Highlights Potential for a Complex Dataset

It has often amounted to little more than background noise. Now, engineers with one of the largest shale producers in the US consider the water-hammer signal to represent a potential trove of insight into stimulation performance. ConocoPhillips has spent almost 3 years developing a new approach to water-hammer analysis and recently shared the first public details of that work in a technical paper (SPE 204154). Perhaps the core takeaway is that within a few minutes of post-stage data, a picture of reservoir and stimulation quality is available. The challenge lies in how to bring that picture into proper focus. The water hammer is a pressure pulse that moves through the wellbore at the speed of sound in fluid, or around 5,000 ft/s, which is more than four-fold the speed of sound in air. Its name comes from the often-audible slam made on one end of the pipe when a column of moving fluid is slowed or halted. One is usually generated as a valve is turned, or a pump slowed or stopped at the end of a fracture stage. This makes the water hammer ubiquitous in the context of hydraulic-fracturing operations the world over. As the wave bounces up and down the wellbore it generates noticeable pressure spikes on wellhead gauges. These oscillating signatures have been the subject of industry intrigue for decades. They’ve also proven to be difficult to decipher and trust. As such, the water hammer has not entered into the shale sector’s pantheon of fracture-design inputs. ConocoPhillips’ ongoing research and development project may help change that. Based on a review of treatment data from more than 150 of the operator’s low-permeability wells from an unnamed field in North America, those with fast-decaying water-hammer signals amounted to the best performers, achieving an output equivalent to 94–110% of their estimated recoveries. On the other hand, wells with more prolonged or low decay rates commonly fell 10–20% below their original type curve. “The high decay rates indicated more near-wellbore fracture surface area, which related to higher well productivity. While conversely, low decay rates mean less near-wellbore friction, longer fractures, lower well productivity,” explained Dung “Zoom” Nguyen. Nguyen is a staff completions engineer at ConocoPhillips and coauthor of the paper that she presented at the annual SPE Hydraulic Fracturing Technology Conference in May. She elaborated that analysis on frac hits, or fracture-driven interactions (FDIs), supports the relationship between fracture geometry and water-hammer decay rates, i.e., low decay rates equate to fewer, longer, and less-complex fractures.

A Head Formulation for the Steady-State Analysis of Water Distribution Systems Using an Explicit and Exact Expression of the Colebrook–White Equation

Steady-state demand-driven water distribution system (WDS) solution is the bedrock for much research conducted in the field related to WDSs. WDSs are modeled using the Darcy–Weisbach equation with the Swamee–Jain equation. However, the Swamee–Jain equation approximates the Colebrook–White equation, errors of which are within 1% for ϵ/D∈[10−6,10−2] and Re∈[5000,108]. A formulation is presented for the solution of WDSs using the Colebrook–White equation. The correctness and efficacy of the head formulation have been demonstrated by applying it to six WDSs with the number of pipes ranges from 454 to 157,044 and the number of nodes ranges from 443 to 150,630. The addition of a physically and fundamentally more accurate WDS solution method can improve the quality of the results achieved in both academic research and industrial application, such as contamination source identification, water hammer analysis, WDS network calibration, sensor placement, and least-cost design and operation of WDSs.

Analysis of Unsteady Friction Models Used in Engineering Software for Water Hammer Analysis: Implementation Case in WANDA

Transient events are frequent in water distribution systems. However, until now, most of the applications based on transient analyses are merely theoretical. Additionally, their implementation to real engineering problems is limited due to several physical phenomena accompanying transient waves, which are not accounted for in the classic approach, such as unsteady friction. This study investigates different unsteady friction models’ performance in terms of accuracy, efficiency, and reliability to determine the most-suited engineering practice. As a result of this comparison, Vítkovský’s unsteady friction model was found to be the best fit and was then implemented in WANDA commercial software. The implementation was verified with experimental data based on a reservoir–pipe–valve system. The model proved excellent performance; however, it was noticed that it fell short in simulating plastic pipes, where viscoelastic effects dominate. The upgraded software was then tested on different hydraulic networks with varying pipe materials and configurations. The model provided significant improvement to water hammer simulations with respect to wave shape, damping, and timing.

On the transient flow behavior in pressurized plastic pipe-based water supply systems

Abstract Plastic material pipes such as high- or low-density polyethylene (HDPE or LDPE) are increasingly used in new or renewed water supply systems. Therefore, analysis of water hammer surge-waves initiated into such piping systems deserves investigation. The 1-D pressurized-pipe flow model embedding the Ramos formulation was used to describe the flow behavior in the elastic and plastic pipe-based hydraulic system. Numerical computations were performed using the method of characteristics. First, the numerical solver was validated against experimental data, available from the literature. Then, the proposed solver was applied to explore the transient pressure-wave behavior resulting from the power failure to a pumping station. Results evidenced the severity of such a scenario with regards to induced positive and negative pressure-wave magnitudes. Furthermore, the findings of this study suggested that plastic pipe-wall materials allowed a significant attenuation of pressure-wave magnitude in conjunction with the expansion of the pressure-wave oscillation period. It was also found that the observed attenuation and expansion effects depended strongly upon the plastic material type. In this respect, the results revealed that LDPE provided a better trade-off between the two last effects than HDPE.

Experimental and numerical investigations of water hammer analysis in pipeline with two different materials and their combined configuration

Water conductor system in hydro power plants experience water hammer or hydraulic transient events regularly and may cause damage of civil and mechanical components. Recently developed viscoelastic pipes such as Glass Reinforced Fibre Plastic (GRP) have been started in use to replace metallic pipes in hydro power and water supply plants. However, studies on combinations of metallic-viscoelastic pipeline behaviour for water hammer conditions are limited especially for varied diameter and combinations of different pipe materials. In this paper, the response of water hammer pressure in metallic-viscoelastic pipeline is investigated experimentally and numerically. Two different pipe materials i.e. Mild Steel (MS) and GRP and their metallic-viscoelastic pipe configuration was used to investigate and analyze the water hammer pressure generation and compared with pressure developed in single material pipeline. An experimental setup was designed and fabricated to carry out the water hammer test. The numerical simulation was carried out by using the method of characteristics (MOC). The GRP pipeline was found more effective to reduce the water hammer pressure and a combination of GRP + MS pipeline (GRP for initial reach having low pressure and MS for later reach having high pressure) in the plants, where GRP pipeline alone cannot be used due to manufacturing limitations of pressure and size, can be used to reduce transient pressure in the water conductor system.

Unified Matrix Frameworks for Water Hammer Analysis in Pipe Networks

Several numerical methods have been developed to analyze water hammer dynamics, and among these, the method of characteristics (MOC) is the most widely applied, establishing the time-dependent characteristic equations that account for the components of the unsteady flow. This paper introduces a matrix formulation of the characteristic equations, which is based on an assumed initial incidence matrix that describes the topology of the network, including loops. Unlike traditional MOC, the matrix equations are used to simultaneously solve for all pressures and flows in the network, at each time step, as a linear function of the pressure and flow at all locations in the network in the previous time step. Two solution procedures are proposed, both of which solve for pressures by decomposing the linear systems of equations into a reduced linear system of equations that is on the order of the number of nodes, and use the resulting pressures to update the flow vector, that is on the order of the number of pipes or pipe reaches, at each time step. The proposed solution procedures are not dependent to the network topologies. For different shapes of pipe network, the formulation remains unchanged and the user need only enters different input data in the form of vectors to find the solution using matrix–vector multiplications at each time step. Fast linear solvers can also be implemented to speed up the process, because the linear system of equations at the core of these algorithms is a Stieltjes matrix. These solution procedures are applied for matrix formulations of two numerical examples, and the resulting nodal pressure and pipe flow at each time step are nearly identical.

Water Hammer Analysis in the main pipe-line for the proposed Taq-Taq Dam irrigation project in Iraq

A water hammer is a common problem occurring in water distribution systems, such as water transport pipelines. Transient hydraulic occurs in the distribution system, which may cause system failure due to pipe collapse or bursting. In this paper, an irrigation pipeline system of the proposed Taq-Taq dam (north-eastern part of Iraq) is used to represent the common situation of lifting water from the dam reservoir to another higher reservoir (irrigation project reservoir) through a pipeline. The transmission line is subject to a potential water hammer where the water level in two main reservoirs is controlled at both ends. The hydraulic simulation model used in the design and analysis of hydraulic and transverse behaviour (water hammer) was adopted by a software named Bentley HAMMER through two scenarios (with and without control device). An operational control measure was proposed to be adopted by a surge tank for minimizing the probability of the occurrence of the water hammer, also to protect the dam from this problem. The results showed that using of surge tank protects the pipe network effectively from the effect of water hammer. Distribution profiles of velocities and pressures on the pipeline indicate that the water hammer on the pipeline was clearly reflected.

Water hammer analysis when switching of parallel pumps based on contra-motion check valve

In this paper, the close process of contra-motion check valve in countercurrent pressure difference is studied in nuclear power plant experimental circuit. The transient mathematical model is established. Through the dynamic grid technique, transient flow field in different conditions of valve closing are calculated, and dynamic properties of valve head closing process is analyzed. Through the CFD transient analysis, inherent damping principle and inhibition of water hammer principle are revealed. By writing water hammer analysis, the inhibitation ability of water hammer in typical six conditions is analyzed. At last the performance verification experiments show that contra-motion check valve can effectively inhibit water hammer in the process of parallel double pump switching transition.

Research on the protection of pipelines with multiple column separation and water hammer of cavities collapsing

In long distance water transfer project, pipeline fluctuation, easy to produce multiple column separation phenomenon, then the water hammer of cavities collapsing is greatest harm to the pipe. Summarizing the previous research results, mechanism analysis of water hammer of cavities collapsing and theoretical calculation model, and introduces the main protective equipment and boundary conditions. After long-term practice, constant speed buffer air valve and Two-way Surge Tower effect remarkable on water hammer of cavities collapsing.

Water Hammer Phenomenon: Analysis and Solutions ظاھرة الطرق المائى : التحلیل والحلول

تعتبر المطرقة المائية ظاھرة معقدة يجب التعرف على تأثيرھا الضار حتى نجدالحلول المناسبة لمنع ھذه الاضرار وتنشأ المطرقة المائية نتيجة التغيرالمفاجى فى سرعة المياه داخل الأنابيب نتيجة انقطاع المغذى لمحرکاتالطلمبات فجاة أو القفل المفاجئ للمحابس أثناء التشغيل وينتج عنھا ارتفاعوانخفاض مفاجئ فى الضغط وظھور موجة ضغط موجبة وسالبة تتحرکبسرعة الصوت مما يسبب أضرار بالغة مثل ( انفجار المواسير – تدميرالطلمبات – تدمير المحابس .... ) وتھدف الدارسة إلى تحليل ووضع الحلوللظاھرة الطرق المائى أو منعھا عن طريق ترکيب أجھزة الحماية مثل( خزاناتالفائض – خزانات المياه والھواء – محابس الأمان – محابس الھواء ) تناولالبحث تطبيق عملى على أحدى منظومات محطات الرى فى مشروع الصالحيةالزراعى حوالى ۳۳٥٥۱ فدان ( محافظة الاسماعيلية ) واشتمل العمل علىالقياسات العملية للتصرفات والضغوط داخل المواسير فى حالة السريانالمنتظم وتم تسجيل أعلى ضغط وأقل ضغط على اللوحة الرئيسية للتشغيل عندانقطاع التيار وفى وجود خزان المياه والھواء تم التحليل باستخدام الطريقةللحصول على النتائج التسجيل وأسفرت ( AFT impulse ) النظرية الحسابيةالنتائج إلى أن استخدام أجھزة الحماية مثل خزانات المياه والھواء أو خزاناتالفائض تؤدى إلى حماية منظومة الرى من ظاھرة الطرق المائى کذلک کانتلحل مشاکل الطرق المائى CFD من النتائج أھمية وسھولة الطرق الحسابيةبالمقارنة إلى التحليل النظرى أو العملى AFT Impulse باستخدام برنامجتطابقت النتائج العملية والنظرية والحاسبية إلى حد کبير .Abstract: Water hammer (hydraulic transient) is a complex phenomenon. The cause of a hydraulic transient is the rapid change in the velocity of the flow in a closed pipe due to sudden power failure or sudden valve closure which generates high and low pressure waves transmit through the pipe line with a speed of sound. The generated waves can cause serious problems in the pipeline system such as pipe burst, pumps and valves failure. The aim of the study is to analyze experientially, theoretically and computationally to find out a solution for this phenomenon. This was done through applying some practical methods techniques of water hammer control devices used in irrigation pumping systems. In Salhia Agriculture Project site, Ismailia 33551 feddan were selected to carry out the water hammer investigation. The steady state calculation was first executed to measure the flow rate and the head, unsteady state flow calculation was carried out to identify the maximum and minimum pressure during the sudden pump trips. The results showed that the control devices such as the air vessels or surge tanks would mitigate the pressure rise and prevent the formation of negative pressure. Water hammer analysis using AFT impulse program is an effective and reliable tool to choose the required surge protection device. Installation of surge control device in the system such as one air vessel 50 m3 air volumes provides an acceptable level of protection to the irrigation pumping systems, as there are no cavitations at the pipeline and the maximum pressure reduces from 11 bars to 6 bars. A good a agreement among the experimental, theoretical and computational associated results was found.

Numerical and Experimental Investigation of the 4-Quadrant Behavior of Different Mixed Flow Diffuser Pumps

Besides operating a centrifugal pump under normal conditions there are additional operating conditions possible; for example, a pump operated as turbine. Another example would be a pump trip where there are several abnormal operating conditions possible when the direction of flow and/or the direction of rotation are changing. The machine behavior in every possible operation condition can be represented by the complete pump characteristics, often called the 4-quadrant (4Q) behavior of a centrifugal pump. To gather the 4Q behavior, a test rig allowing the flow direction as well as the rotation direction to be reverted is necessary, with time-consuming measurements at variable positive and negative discharge in both directions of rotation the complete pump characteristics are evaluated. In the present study, an approach to investigate the complete pump characteristics by means of computational fluid dynamics (CFD) calculations is presented. With steady-state calculations and additional transient CFD investigations in the normal operating conditions, the whole pump characteristics were calculated accurately. Two different types of mixed flow diffuser pumps were investigated—one equipped with adjustable impeller blades, the second one with comparable low specific speed. Experimental verifications have shown a remarkably good agreement. Furthermore, an exemplary numerical waterhammer analysis shows the successful application of the presented approach.

SimHydraulics approach to water hammer problems with the development of new formulas for static pressure diameter coefficient

Water hammer analysis and prediction is of overriding importance for operation safety of hydraulic systems. Therefore, the verification of computer codes capability to model and simulate water hammer is a very interesting topic for the analysis of different fluid-filled pipeline systems. Until now, transient approach of SimHydraulics is not developed, and the validity of this approach against benchmark examples, has never been investigated in scientific literature. In this paper, a numerical model of a reservoir-pipelines-valve system is created using Matlab SimHydraulics software. The main component of this model is the Segmented Pipeline with wall compliance parameters: the viscoelastic process time constant τ and the static pressure diameter coefficient K P for which new formulas were derived and validated. The numerical model is performed to solve transient flow problems caused by closure of a valve and the obtained results are presented and compared with those using the method of characteristic. Also, the effectiveness of the transient model of SimHydraulics is evaluated by comparing the obtained numerical results with the most pertinent experimental results found in the literature. The proposed transient model was adapted for the investigation of more complex piping systems. The results of this study show the ability of the SimHydraulics model to predict the pressure oscillation behavior accurately in all cases considered. This study provides useful information for future research in pump transient simulation using SimHydraulics.

CPR1000核电厂凝结水系统管道水锤效应研究

CPR1000核电厂凝结水系统管道水锤效应研究

Calculation of the hydraulic stroke in the Mlecva MHPP pipeline caused by sudden closing of the closer

Water hammer is a pressure surge phenomenon that occurs in pressurised pipelines as a result of a change of the flow velocity. This paper presents analyses of water hammer in the pipeline of mini-hydro power plant (MPP) Mlečva in Bratunac, Republika Srpska. The objective of this paper is to analyse water hammer in the pipeline as well as to asses risks to the system from pressure surge The paper presents a description of the problem, equations of water hammer mathematical model and water hammer analysis using the software SurgePRO (Transient flow analysis) and Bentley HAMMER V8i.