Since 2007, DRG has hosted a large number of lectures for an audience of stress and mechanical engineers. With around four lectures a year, many subjects have been presented and not unusual, have been followed-up by a lively discussion during the informal drinks afterwards.
The overview of lectures of previous years can be viewed below. If available, the lecture notes can be downloaded, or – for the more recent lectures – the lecture can be viewed online.
Speaker: Richard Fawcett of Dynaflow Research Group
In this lecture a range of transient effects will be introduced. It will be shown why they occur and what their effect on a stress analysis is. A number of typical projects conducted by DRG will be used to demostrate how these transient effects can be included in a stress analysis.
Speaker: Luuk Hennen of Dynaflow Research Group
Multiphase flow in piping systems can pose a serious hazard to system integrity. Slugs that form in piping, due to a two-phase flow that is fed to the system, can impose big shock loads on piping components such as elbows, tees and valves. This can be a one-time event or cyclic by nature. Such phenomenon can therefore result in dynamic behaviour of the piping itself such as vibrations or shifting of the entire line.
In contrast to pipe vibrations due to connecting rotating equipment, multiphase flow often results in vibrations with a low frequency and high amplitude. Those vibrations can be easily observed by the naked eye. Such vibrations are regularly experienced in furnaces, water feed lines or wellhead lines and can result in mechanical fatigue failure, immediate pipe failure or broken supports. Additionally, the presence of entrapped gas in the system may result in large pressures, significantly exceeding the system design pressures.
Different approaches for solving vibration issues due to two-phase flow will be presented from risk assessment to stress calculations and associated mitigation methods. Often accelerometer measurements are taken to substantiate dynamic calculations. Challenges for such projects include balancing between required system flexibility and sufficiently supporting to absorb slug loads and the assessment of the actual slugging conditions.
Speaker: Oliver Oxtoby of Engys UK
Packed beds and multiphase flows are two common features of industrial processes such as furnaces and reactor vessels, and yet the combination of the two is sparsely covered by the literature on numerical modelling. Further applications include wave action on harbour breakwaters and multi-fluid flows in rock beds.
In this presentation, we describe our efforts to improve upon the multiphase porous modelling capabilities in the OpenFOAM® toolset. These developments comprise improvements to the handling of free surfaces on non-orthogonal meshes, as well as a numerical method for handling arbitrary heterogeneous porosity fields, possibly including discontinuities, without introducing instabilities or spurious oscillations. This allows for a general porosity distribution to be specified as just another field.
Speaker: Michiel Tukker of Deltares
This presentation discusses the validation of the 1D pipeline simulation software WANDA with experiments. The Wanda simulation software is used to perform multiple studies for gas wells and transport pipelines to assess the functioning of High Integrity Pressure Protection Systems (HIPPS) and the protection against excessive high pressures.
The experiments have been performed in the large-scale multiphase flow research facility, the Alpha Loop, a 320 m long pipeline system with a diameter of 200 mm.
The project is investigates the behaviour of a slug at rest, which is accelerated due to expanding gas in a long pipeline system. Measurements of the pressures, temperatures and slug position are recorded during the experiment. The movement of the slug has also been recorded using a high-speed camera to get a better understanding of the slug.
The experiment setup has been modelled in WANDA and the model was calibrated using measurements where there is no slug, but only gas flows through the pipeline. The simulation results are then compared with the measured slug velocities, pressures and temperatures from the experiment. The results show good correlation between the calibrated model and the measurements. However, observed 3D phenomena in the experiment due to the large scale are not included in the current 1D model of Wanda, causing the 1D model to predict higher slug velocities than were recorded in the experiment.
Speaker: Richard Fawcett of Dynaflow Research Group
Sudden transient events in a piping system such as the fast closure of an emergency shut-down valve or the fall out of a pump lead to pressure transients in the flowing fluid. These pressure transients (surge waves) can lead to pressures exceeding the line pressure, or excessive lateral movement and bending stresses in the piping.
Through a series of cases based on DRG’s project experience typical operating scenarios which can lead to excessive pressure surges will be discussed. Where DRG’s experience ranges from preventing failures at the design phase to root cause analysis of failures in an operating system. Through a number of cases, a series of typical critical issues will be explained and how to design for these so as to ensure a robust system will be demonstrated.
In lines operating at low pressures, cavity pockets may also arise due to surge. As the pressure recovers back above the fluid vapour pressure, the cavity will collapse and the two fluid columns will collide with each other. This collision, like the original surge wave, can result in large amplitude pressure waves. Through a series of examples it will be explained how cavity pockets can form, the detrimental effects these can have on the piping system and how to avoid their occurrence.
Speaker: Ruud Henkes of TU Delft / Shell Projects & Technology
A possible new development concept for Floating LNG may include a single flowline along the sea floor that splits into dual or more flexible risers. Since the gas co-produces condensate and water, design rules are needed for the splitting of the phases at the riser base manifold.
Ideally the phase volume ratio of the multiphase flow should be fully equal over the two risers and remain the same as in the flow line. The hypothesis is that maldistribution can occur if the gas flow rate in the risers is so low that it gives churn flow or hydrodynamic slug flow in the risers, whereas an equal split is expected if the gas flow rate is sufficiently high to produce annular flow. To study this we have carried out lab experiments and CFD simulations.
The flow facility at the Shell Technology Centre in Amsterdam transports air and water through a 2”, 100 m long flowline, splitting into dual 15 m high risers, having a diameter of 2” or 1.25”. The pressure is atmospheric at the riser top. For the splitting configuration, we tested both a non-symmetric lay-out (so called Branching Tee) and a symmetric lay-out (so-called Impacting Tee). We also created the splitting curve by systematically changing the opening of the chokes at the top of the risers. At low gas flows, for both splitting configurations, a non-symmetric flow split was found, with flip-flopping and hysteresis in the risers. For example, a stagnant liquid flow could develop in one riser, and churn flow in the other riser, with a sudden swap of flow behaviour between the two risers. This maldistribution gradually disappeared as the gas flow rate was increased.
CFD simulations were carried out with the Fluent package using a Volume of Fluid approach for the multiphase flow through the symmetric splitter. As in the experiments, the CFD simulations also give the preference of all flow to be produced though a single riser, with a stagnant liquid column in the other riser. However, in the CFD prediction this misdistribution is found at a lower gas production than in the experiments.
Speaker: Frank Bos of Dynaflow Research Group
An overview of analysis and design methods were given for welds subject to fatigue loading. Special focus was given to welds typically found in pressure vessels and piping.
Speaker: Niels Pörtzgen of Applus RTD Nederland
IWEX is a novel ultrasonic testing method whose development was initiated by Applus RTD. The result of this emerging technique is an actual image of the inspected volume, rather than a plot of the collected signals, which can be used for accurate characterization in terms of size, position and orientation.
Speaker: Wies Hageraats of Dynaflow Research Group
Speaker: Mr. Jan van Houwenhove of Cryonorm Systems
The technical challenges involved in marine LNG fuel systems for inland and seagoing ships, LNG bunkering systems, both land based and installed on ship, LNG regasification systems and LNG/LCNG fill stations.
Speaker: Mr. Mo Zarkan of Elster-Instromet
The transit time ultrasonic flow meters (UFM) from the physics of the ultrasound driving the technology to the building components of an UFM to the challenges of designing a UFM.
The presentation is in Dutch.
Speaker: Mr. Ronald Bringreve from Plaxis
The presentation will show how PLAXIS can be used for the analysis of soil-structure interaction problems, such as applications involving soil retaining walls, tunnels, offshore foundations and pipelines on the sea bottom.
Recent developments also enable a coupling between the PLAXIS software and software for structural analysis in which the soil is usually simplified by means of spring constants. This new feature enables a realistic structural analysis, taking into account non-linear soil-structure interaction effects as provided by PLAXIS.
For more information about this presentation, please contact PLAXIS.
Speaker: Prof. Dr. ir. Ruud Henkes of Shell
Flow assurance covers multiphase flow and solids formation in wells, pipelines, and risers, which form part of the oil and gas production system. New developments involve longer transport distances, colder areas, deeper waters, and more complex fluid compositions.
Speaker: Dr. ir. Eelco van Vliet of Tata Steel
A validation study of an in-house developed CFD model for simulating the multiphase flow of low density particles and bubbles encountered in steel making processes.
Speaker: Dr. Ove Bratland
The presentation described some of the commercial Flow Assurance simulators, some of the pitfalls to avoid when using them, and also discussed their limitations. Some of the limitations are constantly being reduced by the various R&D projects taking place around the world, while others seem to be more fundamental and therefore harder to counter.
Speaker: Dr. ir. Peter Lucas of VSL Dutch Metrology Institute
In the presentation the traceability route for natural gas was discussed in more detail. Furthermore, it was discussed why the operating conditions play such an important role for sound and accurate flow metering. Attention was given to flow rate pulsations as well as the impact of deviating process conditions.
Speaker: Dr.ir. Eugene de Villier of Engys UK
An actuated butterfly valve simulated using an efficient OPENFOAM® and HELYX® based process. The main focus of the investigation is to ascertain the turning moment required to overcome the flow induced forces during the opening and closing of the valve. Of secondary interest is the impact of dynamic effects on the system.
Speaker: Dr.ir. Jos van ‘t Westende of Deltares
When considering the safety of a gas system (e.g. transport pipelines, process vessels), not only the performance under steady conditions should be assessed, but also fast dynamics following unintended valve opening/closure or component failure. A simulation tool that can determine the effects of these fast dynamics and assess the effectiveness of counteracting measures is then a must for designing a safe and reliable system, while not taking too strict and costly measures.
Speaker: Prof. Blair Perot of the University of Massachusetts
The earth is a highly heterogeneous and anisotropic medium. This makes the solution of many oil recovery problems more difficult than they might first appear. This presentation was focused on Darcy flow in permeable solids and will show that many of the issues encountered when computing complex flows can be addressed within the construction of the underlying numerical method.
Speaker: Ing. Ralf Euser of Femto Engineering
The presentation had two different aspects. First, showing how to analyze the nonlinear sloshing motion of free-surface flows inside closed volumes, with respect to contact pressure and liquid height. In addition to this it was demonstrated how to simulate real fluid-structure interaction (FSI) between liquids and solids.
Speaker: Ir. Niels Bos of Dynaflow Research Group
Some recent examples of transient flow analysis projects executed using BOSfluids. These cases will illustrate the transient flow phenomena such as bubble collapse, multi-phase flow, slugging and deep vacuum, relevant for transportation systems.
Speaker: Wouter Slob of Huisman
Mr. Slob explained the boundaries of the Pipelay market and how well the products of Huisman are connected to that. Several Pipelay solutions were presented in detail to provide some technical insight into the world of “Subsea pipelines”.
Speaker: Hein Baartmans of Control Risks
Speaker: Jan Otten of Shell
Shakalin case study
Speaker: Ruud Henkes part-time professor at TU-Delft and Team leader Shell Projects & Technology
Speakers: Wies Hageraats of Dynaflow Research Group, Tom Santegoed of Femto Engineering, Mr. Hulst of HEC
During the lecture the comparison of Ansys, FEMAP and ProMechanica was discussed.