Papers by Philippe Planquart
Procedia Manufacturing
Under the concept of "Industry 4.0", production processes will be pushed to be increasingly inter... more Under the concept of "Industry 4.0", production processes will be pushed to be increasingly interconnected, information based on a real time basis and, necessarily, much more efficient. In this context, capacity optimization goes beyond the traditional aim of capacity maximization, contributing also for organization's profitability and value. Indeed, lean management and continuous improvement approaches suggest capacity optimization instead of maximization. The study of capacity optimization and costing models is an important research topic that deserves contributions from both the practical and theoretical perspectives. This paper presents and discusses a mathematical model for capacity management based on different costing models (ABC and TDABC). A generic model has been developed and it was used to analyze idle capacity and to design strategies towards the maximization of organization's value. The trade-off capacity maximization vs operational efficiency is highlighted and it is shown that capacity optimization might hide operational inefficiency.
EPJ Nuclear Sciences & Technologies
Liquid metal cooled reactors are envisaged to play an important role in the future of nuclear ene... more Liquid metal cooled reactors are envisaged to play an important role in the future of nuclear energy production because of their possibility to use natural resources efficiently and to reduce the volume and lifetime of nuclear waste. Sodium and Liquid lead (-alloys) are considered the short and long term solution respectively, as coolant in GEN-IV reactor. Thermal-hydraulics of liquid metals plays a key role in the design and safety assessments of these reactors. Therefore, this is the main topic of a large European collaborative program (the Horizon 2020 SESAME) sponsored by the European Commission. This paper will present the progress in the project with respect to liquid metal cooled reactor thermal-hydraulics (liquid metal heat transfer, fuel assembly thermal-hydraulics, pool thermal-hydraulics, and system thermal-hydraulics). New reference data, both experimental and high-fidelity numerical data is being generated. And finally, when considering the system scale, the purpose is ...
The renewed interest in reusable launch vehicles has fueled the development of many advanced spac... more The renewed interest in reusable launch vehicles has fueled the development of many advanced space transportation concepts. An interesting method for recovering rocket stages called ’In-AirCapturing’, has been patented by DLR. The winged stages are captured mid-flight and towed back to the landing site by an aircraft, eliminating the need for an additional propulsion system. A critical procedure in the capturing process involves an aerodynamically controlled capturing device attached by a rope to the towing aircraft, performing an autonomous rendezvous maneuver with the launch vehicle. In this paper, the complex dynamics associated with this phase are modelled and examined. This includes the aerodynamics of the capturing device, external disturbances like the turbulent wake of the aircraft and the flexible dynamics associated with the rope. These effects are combined into a multidisciplinary framework and a preliminary control system is proposed. The final open-loop simulation resul...
As far as ground vehicles aerodynamics is concerned, consumption reduction is a major issue for r... more As far as ground vehicles aerodynamics is concerned, consumption reduction is a major issue for reducing the human fingerprint on the Earth. For a car at 100km/h, drag is the major part of resistance to the motion. Since the drag coefficient is closely linked to the flow behavior at the rear of the car, simplified models appeared during the last decades to carry out reference tests. Techniques commonly applied in aerodynamics to study drag and characterize the flow, like balance force measurements, surface visualization, hot-wire anemometry or LDV, are not always enough to deeply understand its nature. The fast growth of the Particle Image Velocimetry technique gives new opportunities for the investigation of the wake mechanism inducing drag.
The thermal-hydraulics challenges of a nuclear reactor are numerous and crucial to be investigate... more The thermal-hydraulics challenges of a nuclear reactor are numerous and crucial to be investigated for the design and safety of new reactors. Numerical simulation through computational fluid dynamics codes or system codes can address a lot of the different challenges, nevertheless the use of water modeling for the study and validation of the thermal-hydraulic behavior of a new primary circuit design remains a very valuable tool. A water model of the heavy liquid metal (HLM) cooled MYRRHA reactor was developed at the von Karman Institute in collaboration with SCK•CEN and has been named MYRRHABELLE. It is a full Plexiglas model at a geometrical scale 1/5 of primary system (design version 1.2) of MYRRHA. The scaling was performed by respecting the Richardson and the Euler similarity with the HLM reactor. A detailed description of the model and of the scaling procedure is provided in this paper. A transparent water model allows the application of non-intrusive optical measurement techni...
Les ecoulements en cuve agitee se retrouvent dans de nombreuses applications industrielles comme ... more Les ecoulements en cuve agitee se retrouvent dans de nombreuses applications industrielles comme l’agroalimentaire, le pharmaceutique, ou encore l’industrie chimique. Les ecoulements presents dans ce type d’installation rotative sont largement tridimensionnels et particulierement non symetriques lorsque la cuve est munie de contre pales. La modelisation de ces ecoulements n’est donc pas aisee, et se complexifie d’autant plus lorsque plusieurs phases coexistent dans la cuve.L’objectif de cette etude conjointe entre l’Institut von Karman et le CETIM est de creer une base de don-nees experimentale pour la validation des codes numeriques destines a la simulation d’ecoulements en cuve agitee. Le projet comprend plusieurs etapes qui vont de mesures en ecoulement monophasique, jusqu’a des mesures diphasiques de melange solide – liquide et liquide – gaz. Cette communication traite des resultats experimentaux de la premiere etape qui se focalise sur l’ecoulement purement liquide.L’installati...
Nuclear Engineering and Design, 2020
This article reports the experimental and DNS database that has been generated, within the framew... more This article reports the experimental and DNS database that has been generated, within the framework of the EU SESAME and MYRTE projects, for various low-Prandtl flow configurations in different flow regimes. This includes three experiments: confined and unconfined backward facing steps with low-Prandtl fluids, and a forced convection planar jet case with two different Prandtl fluids. In terms of numerical data, seven different flow configurations are considered: a wall-bounded mixed convection flow at low-Prandtl number with varying Richardson number (Ri) values; a wall-bounded mixed and forced convection flow in a bare rod bundle configuration; a forced convection confined backward facing step (BFS) with conjugate heat transfer; a forced convection impinging jet for three different Prandtl fluids corresponding to two different Reynolds numbers of the fully developed planar turbulent jet; a mixed-convection cold-hot-cold triple jet configuration corresponding to Ri = 0.25; an unconfined free shear layer for three different Prandtl fluids; and a forced convection infinite wire-wrapped fuel assembly. This wide range of reference data is used to evaluate, validate and/or further develop different turbulent heat flux modelling approaches, namely simple gradient diffusion hypothesis (SGDH) based on constant and variable turbulent Prandtl number; explicit and implicit algebraic heat flux models; and a second order turbulent heat flux model. Lastly, this article will highlight the current challenges and perspectives of the available turbulence models, in different codes, for the accurate prediction of flow and heat transfer in low-Prandtl fluids.
Nuclear Engineering and Design, 2020
The current paper describes the loss of flow (LOF) transient investigated in the MYRRHA reactor b... more The current paper describes the loss of flow (LOF) transient investigated in the MYRRHA reactor by the means of Computational Fluid Dynamics. This scenario is starting from the nominal operation case then the two pumps stop simultaneously. An unsteady solution with resolved interface was considered with calculating conjugate heat transfer through the relevant structures. Due to a postulated event (e.g. loss of the electric grid) the pumps are not powered anymore stops. After the detection of the problem (temperature difference above the core rises with 20 degree) the reactor power is stopped by the safety rods (delay of 1 s). The fuel elements, however, continue to generate residual heat according to the decay heat curve. Due to the loss of the pumps, the pressure difference between the cold and the hot plenum is decreasing, which result in a gravitational flow equilibrating the two free surfaces to the same level. The objective of the work was to determine the flow through the core during the coast down of the pumps and eventual flow reversal into the pump/heat-exchanger box due to the gravitational flow. The simulation revealed that after losing power, the LBE flow reverses into the pumps in less than 0.1 s according to the simulations. In the core there is a brief moment of reverse flow, too, but only after the core is scrammed, therefore, the loss of cold LBE flow is not causing overheat. Once the core is scrammed, the position of the maximum temperature in the system shifts to the Above Core Structure, where the residual hot plume rising from the core impinges to the Above Core Upper Closure. The levels of the lower and upper plenum equilibrate roughly 20 s after the pump failure event.
EPJ Web of Conferences, 2018
The Belgian nuclear research institute (SCK•CEN) is developing MYRRHA. MYRRHA is a flexible fast ... more The Belgian nuclear research institute (SCK•CEN) is developing MYRRHA. MYRRHA is a flexible fast spectrum research reactor, conceived as an accelerator driven system (ADS). The configuration of the primary loop is pool-type: the primary coolant and all the primary system components (core and heat exchangers) are contained within the reactor vessel, while the secondary fluid is circulating in the heat exchangers. The primary coolant is Lead Bismuth Eutectic (LBE). The recent nuclear accident of Fukushima in 2011 changed the requirements for the design of new reactors, which should include the possibility to remove the residual decay heat through passive primary and secondary systems, i.e. natural convection (NC). After the reactor shut down, in the unlucky event of propeller failures, the primary and secondary loops should be able to remove the decay heat in passive way (Natural Convection). The present study analyses the flow and the temperature distribution in the upper plenum by applying laser imaging techniques in a laboratory scaled water model. A parametric study is proposed to study stratification mitigation strategies by varying the geometry of the buffer tank simulating the upper plenum.
Nuclear Technology, 2019
The thermal-hydraulic challenges of a nuclear reactor are numerous and mastering them is crucial ... more The thermal-hydraulic challenges of a nuclear reactor are numerous and mastering them is crucial for the design and safety of new reactors. Numerical simulation through computational fluid dynamics...
Nuclear Engineering and Design, 2019
Heat Transfer Engineering, 2019
This study considers the decay heat removal through passive systems (i.e., natural convection) in... more This study considers the decay heat removal through passive systems (i.e., natural convection) in the pool-type experimental reactor MYRRHA (SCKCEN). The low velocities associated with natural convection may cause a degradation of the thermal mixing in the upper plenum of the reactor: buoyancy dominated phenomena, such as stratification, buoyant jets or convective cells may occur. The large temperature gradients associated with these phenomena may induce thermal loads on the structure, compromising its integrity. The objectives of this work are, in order, (1) achieving an understanding of the fluid mechanics leading to the formation of thermal gradients in the upper plenum and (2) mitigating the temperature gradients the upper plenum's geometry. The methodology chosen to address the problem is experimental. A ''two-dimensional'' water facility modeling a slab of the reactor's primary loop was designed. Simultaneous measurements of velocity and temperature were performed in the model's buffer tank using thermocouples and innovative optical imaging techniques. It was observed that vertical thermal gradients develop in the tank because of the combined effect of stratification and advection. Important reductions of local gradients were observed when changing porosity and position of upper plenum's buffer plates.
Nuclear Engineering and Design, 2017
For the safety assessment of Heavy Liquid Metal nuclear reactors under seismic excitation, sloshi... more For the safety assessment of Heavy Liquid Metal nuclear reactors under seismic excitation, sloshing phenomena can be of great concern. The earthquake motions are transferred to the liquid coolant which oscillates inside the vessel, exerting additional forces on the walls and internal structures. The present study examines the case of MYRRHA, a multipurpose experimental reactor with LBE as coolant, developed by SCK•CEN. The sloshing behavior of liquid metals is studied through a comparison between mercury and water in a cylindrical tank. Experimental investigation of sloshing is carried out using optical techniques with the shaking table facility SHAKESPEARE at the von Karman Institute. Emphasis is given on the resonance case, where maximum forces occur on the tank walls. The experimental cases are reproduced numerically with the CFD software OpenFOAM, using the VOF method to track the liquid interface. The non-linear nature of sloshing is observed through visualization, where swirling is shown in the resonance case. The complex behavior is well reproduced by the CFD simulations, providing good qualitative validation of the numerical tools. A quantitative comparison of the maximum liquid elevation inside the tank shows higher values for the liquid metal than for water. Some discrepancies are revealed in CFD results and the differences are quantified. From simulations it is verified that the forces scale with the density ratio, following similar evolution in time. Overall, water is demonstrated to be a valid option as a working liquid in order to evaluate the sloshing effects, for forcing frequencies up to resonance.
Proceedings of the 2014 International Conference on Quantitative InfraRed Thermography, 2014
An experimental investigation is carried out on a semi-industrial prototype of regenerative roll ... more An experimental investigation is carried out on a semi-industrial prototype of regenerative roll quench system. It allows the determination of the thermal contact conductance between a roll and a moving strip. The application of the quantitative infrared thermography leads to the angular evolution of the strip temperature while the mean roll temperature is obtained by using thermocouples connected to a wireless telemetry data acquisition system. The experimental facility and the thermal model associated to the thermal conductance determination are presented. The results emphasize the effect of operating parameters such as the velocity, initial temperature and tensile strength of the strip. Modeling of the interfacial thermal conductance is finally proposed.
Proceedings of the 2004 International Conference on Quantitative InfraRed Thermography, 2004
Proceedings of the 2010 International Conference on Quantitative InfraRed Thermography, 2010
The World Solar Challenge is a solar-powered car race, which cover 3021 km from Darwin to Adelaid... more The World Solar Challenge is a solar-powered car race, which cover 3021 km from Darwin to Adelaide. Most of the vehicles participating at this race can be defined as Ultra-Streamlined body; the drag being mainly produced by skin friction. In designing such vehicle, it is important to localize the area where transition from laminar to turbulent flow will occur. The location of transition will affect the overall drag coefficient of the vehicle. Moreover its determination by CFD simulation is a challenging task. This paper presents an experimental study based on momentum-heat transfer analogy, which has been carried out in the VKI-L1A subsonic wind tunnel. The infrared thermography is applied on a scaled model of the Umicore solar car, which was designed for the World Solar Challenge.
Proceedings of the 2008 International Conference on Quantitative InfraRed Thermography, 2008
The paper describes an experimental investigation of convective heat transfer in case of planar a... more The paper describes an experimental investigation of convective heat transfer in case of planar air jet impinging a hot V-shaped surface. In such a flow configuration the jet experiences a flapping behaviour leading to a stable self-sustained periodic flow characterized by a constant Strouhal number. To determine the timedependent mapping of the convective heat transfer coefficient infrared thermography is used in connection with a very thin metallic-foil of low heat capacity for the test surface, which is heated by Joule effect. The effect of the crucial parameters on heat transfer is analyzed.
Nuclear Engineering and Design, 2017
Numerical analysis of the thermohydraulic behavior of the innovative flexible fast spectrum resea... more Numerical analysis of the thermohydraulic behavior of the innovative flexible fast spectrum research reactor, MYRRHA, under design by the Belgian Nuclear Research center (SCK•CEN) is a very challenging task. The primary coolant of the reactor is Lead Bismuth Eutectic, LBE, which is an opaque heavy liquid metal with low Prandtl number. The simulation tool needs to involve many complex physical phenomena to be able to predict accurately the flow and thermal field in the pool type reactor. In the past few years, within the frame of a collaboration between SCK•CEN and the von Karman Institute, a new platform, MyrrhaFoam, was developed based on the open source simulation environment, OpenFOAM. The current tool can deal with incompressible buoyancy corrected steady/unsteady single phase flows. It takes into account conjugate heat transfer in the solid parts which is mandatory due to the expected high temperature gradients between the different parts of the reactor. The temperature dependent properties of LBE are also considered. MyrrhaFoam is supplemented with the most relevant thermal turbulence models for low Prandtl number liquids up to date.
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Papers by Philippe Planquart