Evaluation of Numerical Methods Applied in the Analysis of the Transient Flow of Pipeline Systems

Author(s):  
Bruno F. Flora ◽  
Raphael I. Tsukada ◽  
Vinícius M. Rodrigues ◽  
José R. P. Mendes ◽  
Adriane S. B. Serapião

Brazilian subsea exploration is increasing specially after the post salt petroleum field discovery. Several challenges have been imposed for the production of those fields. In this scenery, the transport of oil and gas from the production field to the continent is a problem, especially when the fields are located at a great distance from the coast. A possible solution could be the use of subsea pipeline systems, for the transportation of the fluids produced from the petroleum wells. For the pipeline system design it is highly recommended the evaluation of the transient flow, considering the water hammer phenomenon. The definition for this phenomenon is given by the pressure variation due to operation singularities in the pipe system. The disruption in the flow originated by the operation of valves or failure of a pump can be listed as some of the main causes of the water hammer. The basic equations to model the water hammer in fluid mechanics comes from two partial differential equations, the equation of continuity and momentum. The solution of those equations can be obtained by different numerical methods. In this context, this work seeks to contrast results obtained by finite difference method (FDM), the method of characteristics (MOC) and finite elements method (FEM) solutions for the water hammer problem. Those numerical methods were implemented and used to solve a simple system, which are composed of an infinite reservoir, a pipeline and a valve. In this case the valve is closed, originating the water hammer phenomenon. Although it can be considered a simple problem, it allows the evaluation of those numerical methods. Performance, convergence and accuracy were evaluated in order to support the choice of the best numerical method for the development of a numerical simulator used in complex and greater pipeline system design.

2019 ◽  
Vol 21 (5) ◽  
pp. 708-726 ◽  
Author(s):  
Xiaoqin Li ◽  
Xuelin Tang ◽  
Min Zhu ◽  
Xiaoyan Shi

Abstract In the pumping station, the main feedwater system and the reactor system of nuclear power plant, power-supply failure causes strong hydraulic transients. One-dimensional method of characteristics (1D-MOC) is used to calculate the transient process in the pipeline system while three-dimensional (3D) computational fluid dynamics is employed to analyze the turbulent flows inside the pump and to obtain the performance parameters of the pump, and the data exchanges on the boundary conditions of the shared interface between 1D and 3D domains are updated based on the MpCCI platform. Based on the equation of motion of the pump motion parts, the relationship between the external characteristics and the internal flow field in the pump is further investigated because the dynamic behavior of the pump and the detailed fluid field evolutions inside the pump are captured during the transition process, and the transient flow rate, rotating speed, and pressure inside the impeller are comprehensively investigated. Meanwhile, compared with the data gained by experiment and traditional 1D-MOC, the relative errors of rotating speed and the flow rate obtained by 1D-3D coupling method are smaller than those by 1D-MOC. Furthermore, the influences of the main coupling parameters and coupling modes on the calculation results are analyzed, and the cause of the deviation is further explained.


2018 ◽  
Vol 11 (3) ◽  
pp. 47-53
Author(s):  
Nisreen J. Rasheed

Various protection methods can be used for protecting the pipeline system from the impact of water hammer. Which includes the use of special materials for supporting the pipeline and the installation of special devices such as surge tanks, relief valves, and air chambers. In this study, to protect the pipeline system and reduce the effect of water hammer, surge tank has been used. Governing equations of transient flow with and without surge tank is numerically simulated using MATLAB software. Sensitivity analysis was investigated using several variables such as pipe diameter, wave’s velocity and friction factor. Method of characteristics (MOC) was implemented in this study. It was found that the diameter and friction factor of pipe have a significant impact on the results of transient flow and surge tank compared to the effect of wave’s velocity. It has been reached that the capacities of surge tanks at diameter (1m), are (1475m3) at first, second and fourth stages, (1360m3) at third and fifth stages and (570m3) at sixth stage. And at diameter (1.2m), the capacities are (1700m3), (1530m3) and (1475m3) at first, second and third stages respectively. But at diameter (1.4m), the capacities are (1590m3) at first and second stages. For all values of wave’s velocity, the capacities of surge tanks are (1760m3), (1530m3) and (1420m3) at first, second and third stages respectively. But the capacities of surge tanks at friction factor (0.007) are (1810m3), (1585m3) and (1245m3) at first, second and third stages respectively. However, for the capacity of surge tanks at the friction factor (0.008), it was mentioned when the surge tanks capacity of the diameter (1.2m) was mentioned. And when the friction factor is (0.009), the capacities are (1460m3) at first stage, (1415m3) at second and third stages and (570m3) at fourth stage


Author(s):  
Junrong Wang ◽  
Zhiguo Wei ◽  
Jinlan Gou ◽  
Qi Xiao ◽  
Shaodan Li ◽  
...  

In the pipeline system of nuclear industry, shock wave pressure in a pipe will be caused by the fast closing check valve after the pumping stops. This phenomenon is known as water hammer, which brings hidden danger to the security and reliability of the pipeline system. Specially, water hammer may cause serious damage on the pipeline system by the valve misoperation, by the valve malfunction, or by other unexpected events. A vortex diode is used as a highly reliable check-valve in nuclear applications, where it mainly benefits from the intrinsic properties of no moving parts and no leakage. In this paper, we proposed a novel method based on a vortex diode to protect water hammer. In the traditional analysis, a simple one-dimensional (1D) model is often used to simulate the water hammer. However, it is difficult to get the transient flow characteristics in a vortex diode using a 1D model. Thus, a three-dimensional (3D) model using computational fluid dynamics (CFD) is proposed to analyze water hammer in a pipeline system with a vortex diode. The 3D model was firstly verified by comparing the numerical results of CFD with experimental results of a water hammer test. Based on the 3D model, the water hammer was simulated at different inlet conditions in a pipeline system with a vertex diode. In order to investigate the vortex diode used as a leaky check-valve, the inlet pressure was decreased by the corresponding value of pump head to simulate the pump stop after the quasi-steady state was achieved in the vortex diode. It is found that the pressure fluctuation of water hammer is comparable to the pump value, which is not varying with initial velocity in the pipeline system. Thus, we have proved that a vortex diode in the pipeline system acts significantly in suppressing pressure fluctuation of water hammer. This study presents a CFD-based numerical method for water hammer and could be useful in protecting water hammer in nuclear industry.


2020 ◽  
Vol 143 (4) ◽  
Author(s):  
Bagaragaza Romuald ◽  
Zhang Jian ◽  
Yu Xiao Dong ◽  
Dusabemariya Claire

Abstract The simulation approach of pipeline systems, pressure regulating valve (PRV), and hydropneumatic tank (HPT) in hydropower plants (HPP) is performed. The article used suitable protection devices such as hydropneumatic tank and pressure regulating valves to protect the hydro-electric system against water hammer negative effects. The method of characteristics solves hydraulic transient in the HPP system. This article simulates transient phenomena in a hydro-electric power system using FORTRAN language. The aim was to find out and diminish the water hammer at the entrance of the spiral case as well as the pipeline system. The paper has four major philosophies: simulation with no protection, simulation with hydropneumatic tank, simulation with pressure regulating valve, and the combination of hydropneumatic tank with the pressure regulating valve. The results show that a combination of the pressure regulating valve and the hydropneumatic tank is adequate appliances to lessen the effect of water hammer/transient flow in a hydropower plant system. However, in the transient process of the water diversion system, the gas' kinetic characteristic in the hydropneumatic tank has certain complexity when there is high fluctuation in the surge chamber. The study proved that the wicket gate's stepwise could cut down the impact of the water hammer automatically than applying the linear closure law on the network. The automated pressure regulating valve with a high opening stepwise can decrease the negative impact of water hammer significantly. The results from this research paper show that pipeline diameter has crucial factors that influence hydraulic transient in hydropower plant systems.


1974 ◽  
Vol 14 (02) ◽  
pp. 165-178 ◽  
Author(s):  
H.H. Rachford ◽  
Todd Dupont

Abstract The cost-effective design of real pipeline systems must consider thetransient response induced by equipment failure and sales rate changes. Hereare described methods developed over the past decade for simulating slowtransient response; these are followed by a presentation of a new variationalmethod. The latter is formulated to treat fast as well as slow transients, andgives results in excellent agreement with data for diverse cases. The computer resources required are small enough that a 1,000-pipe networkcan be simulated in core on widely available computing facilities (CDC 6600).On the average, 1 hour of 1,000-pipe system operation can be simulated in 100seconds of CDC 6600 central processor time. Introduction To design and operate a gas transmission system cost-effectively requiresaccounting for its response under unsteady or transient conditions. Even thoughcare is given to the optimum design of a system to support steady loads, suchloads represent only a theoretical condition. Actua1 operations invariablyencounter transient states. The loss of a compressor, the addition or loss ofsupply or sale points, replacement of equipment, and customers who demandvariable sale rates are a few of the causes of line transients. The design for cost-effective operation of a system should be completed beforeany capital is spent. For pipeline systems this should begin with optimizingthe required facilities to meet the projected sales rates. But engineering isnecessary beyond that to provide the pipe and compression for steady deliveryof gas. If some of the projected sales are time varying, a quantitative studyshould be made of the fraction of the varying demand that can be met by linepack and the fraction that must be satisfied by local peaking facilities. Onlyby approaching the cost optimum among feasible pipe sizes, compression levels, and peaking facility capabilities can cost-effective use be made of availablecapital. Other facets of cost-effective design for operation are the sizing and locationof standby equipment, its relationship to the capacity of the transmissionsystems, and the cost of failure of the system to meet commitments. Anymechanical system is subject to failure. The allowable time for bringingstandby equipment on line so as to meet all commitments depends upon thecapacity of the standby equipment, the capacity and response rate of thetransmission system, and the amount and location of excess compression or othercapacities elsewhere in the system.


2019 ◽  
Vol 36 (9) ◽  
pp. 1644-1662 ◽  
Author(s):  
Olanrewaju Ayobami Omoya ◽  
Kassandra A. Papadopoulou ◽  
Eric Lou

Purpose The purpose of this paper is to investigate the application of reliability engineering to oil and gas (O&G) pipeline systems with the aim of identifying means through which reliability engineering can be used to improve pipeline integrity, specifically with regard to man-made incidents (e.g. material/weld/equipment failure, corrosion, incorrect operation and excavation damages). Design/methodology/approach A literature review was carried out on the application of reliability tools to O&G pipeline systems and four case studies are presented as examples of how reliability engineering can help to improve pipeline integrity. The scope of the paper is narrowed to four stages of the pipeline life cycle; the decommissioning stage is not part of this research. A survey was also carried out using a questionnaire to check the level of application of reliability tools in the O&G industry. Findings Data from survey and literature show that a reliability-centred approach can be applied and will improve pipeline reliability where applied; however, there are several hindrances to the effective application of reliability tools, the current methods are time based and focus mainly on design against failure rather than design for reliability. Research limitations/implications The tools identified do not cover the decommissioning of the pipeline system. Research validation sample size can be broadened to include more pipeline stakeholders/professionals. Pipeline integrity management systems are proprietary information and permission is required from stakeholders to do a detailed practical study. Originality/value This paper proposes the minimum applied reliability tools for application during the design, operation and maintenance phases targeted at the O&G industry. Critically, this paper provides a case for an integrated approach to applying reliability and maintenance tools that are required to reduce pipeline failure incidents in the O&G industry.


Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4071
Author(s):  
Michał Kubrak ◽  
Agnieszka Malesińska ◽  
Apoloniusz Kodura ◽  
Kamil Urbanowicz ◽  
Michał Stosiak

It is well known that the water hammer phenomenon can lead to pipeline system failures. For this reason, there is an increased need for simulation of hydraulic transients. High-density polyethylene (HDPE) pipes are commonly used in various pressurised pipeline systems. Most studies have only focused on water hammer events in a single pipe. However, typical fluid distribution networks are composed of serially connected pipes with various inner diameters. The present paper aims to investigate the influence of sudden cross-section changes in an HDPE pipeline system on pressure oscillations during the water hammer phenomenon. Numerical and experimental studies have been conducted. In order to include the viscoelastic behaviour of the HDPE pipe wall, the generalised Kelvin–Voigt model was introduced into the continuity equation. Transient equations were numerically solved using the explicit MacCormack method. A numerical model that involves assigning two values of flow velocity to the connection node was used. The aim of the conducted experiments was to record pressure changes downstream of the pipeline system during valve-induced water hammer. In order to validate the numerical model, the simulation results were compared with experimental data. A satisfactory compliance between the results of the numerical calculations and laboratory data was obtained.


2012 ◽  
Vol 619 ◽  
pp. 302-305
Author(s):  
Hong Yan Wang ◽  
Wen Sheng Xiao ◽  
Xiu Juan Lin ◽  
Xian Feng Wang

Considering the pollution on the environment using dynamite source in oil and gas exploration, harm and damage to people and building, the vehicle mounted hammer source which can replace dynamite source is presented. This paper describes briefly the basic structure and working principles of the vehicle mounted hammer source. A typical pneumatic circuit is researched and designed. And the pneumatic circuit is designed with the powerful functions of PLC, the hardware and software design are introduced. The system has advantages of strong striking force, high velocity, small gas consumption, simple structure and convenient control.


Author(s):  
Mohadese Jahanian ◽  
Amin Ramezani ◽  
Ali Moarefianpour ◽  
Mahdi Aliari Shouredeli

One of the most significant systems that can be expressed by partial differential equations (PDEs) is the transmission pipeline system. To avoid the accidents that originated from oil and gas pipeline leakage, the exact location and quantity of leakage are required to be recognized. The designed goal is a leakage diagnosis based on the system model and the use of real data provided by transmission line systems. Nonlinear equations of the system have been extracted employing continuity and momentum equations. In this paper, the extended Kalman filter (EKF) is used to detect and locate the leakage and to attenuate the negative effects of measurement and process noises. Besides, a robust extended Kalman filter (REKF) is applied to compensate for the effect of parameter uncertainty. The quantity and the location of the occurred leakage are estimated along the pipeline. Simulation results show that REKF has better estimations of the leak and its location as compared with that of EKF. This filter is robust against process noise, measurement noise, parameter uncertainties, and guarantees a higher limit for the covariance of state estimation error as well. It is remarkable that simulation results are evaluated by OLGA software.


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