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n the French context of increasing renewable penetration and significant nuclear power, the optimal contribution of this energy source is discussed from two viewpoints. On the one hand, from the social planner viewpoint, the nuclear optimum contribution is the one that minimizes the overall electric price, whatever the resulting load factor. The use of screening curves, often implemented to design the optimal power mix is questioned, being highly sensitive to the assumptions. On the other hand, from the plant operator viewpoint, the nuclear power plants need to amortize the capital expenses, hence achieve the longest operating time. With a view to make the two viewpoints meet, we propose to operate nuclear power plants as baseloads and consider modulation through the power use, i.e. supply electricity to the electric system when requested and use the remaining power to produce other valuable products, such as heat or hydrogen.

This paper presents a careful study related to a more efficient energy management between lithium battery (with rated voltage of 24V) and Ultracapacitors (UC) for Hybrid Electric Vehicle (HEV) applications. This association is due to the present trend in the field, knowing that the major drawback of the HEV is the autonomy problem. Thus, using the Hybrid energy source (such as UC + battery) and with a good energy management improves the HEV performances. In this paper, battery and Ultracapacitors (10 cells of 2.7V in series) are coupled to DC-bus using two buck-boost converters. The main contribution of this paper is focused on DC-bus voltage and currents control strategy based on polynomial (RST) controller. Through some simulations in MATLAB/Simulink software and experimental results, the authors present an improved energy management for HEV.

After a halt of four years, the n TOF spallation neutron facility at CERN has resumed operation in November 2008 with a new spallation target characterized by an improved safety and engineering design, resulting in a more robust overall performance and e cient cooling. The rst measurement during the 2009 run has aimed at the full characterization of the neutron beam. Several detectors, such as calibrated ssion chambers, the n TOF Silicon Monitor, a Mi- croMegas detector with 10B and 235U samples, as well as liquid and solid scintillators have been used in order to characterize the properties of the neutron uence. The spatial pro le of the beam has been studied with a specially designed \X-Y

Abstract A flame shape bifurcation in the liquid-fueled two-stage swirled BIMER combustor is studied using Large Eddy Simulations. This combustor, developed at the EM2C Laboratory to study Lean Premixed Prevaporized (LPP) burners, is composed of a two-stage injection system: a central swirled pilot stage fueled with a pressure-swirl atomizer, to sustain a piloting flame, and an outer swirled stage fed with a multi-point injection, to generate the LPP regime. After ignition in the pilot-only operating condition, a V flame is stabilized near the Inner Shear Layer (ISL). When switching to multipoint-only injection, a flame shape transition is observed and the flame bifurcates into a M-shape. In this work, we identify the mechanisms that lead to this bifurcation, and we show that the transition is driven by a complex coupling between the flame, the chamber acoustics and the ISL vortices. By switching to a multipoint-only injection, the fuel is essentially given to the ISL flame, which is mainly premixed. Because of the increased heat release rate and thanks to positive Rayleigh criterion, the quarter wave mode of the chamber is promoted. The ISL vortices, locked to this mode, increase in size until they are large enough to merge the flame in the CRZ, the radial momentum budget forcing the flow topology to switch to a bubble-like structure. Therefore, these results show that it is the existence of two possible flow topologies that renders this flame shape transition possible, the instability being responsible for transferring sufficient energy to the flow to enable the transitioning and the flame then changing its shape simply to adapt to the new topology.

Abstract This paper deals with an optimization of the Stirling engine regenerator’s. Firstly, different materials are experimented (Stainless Steel, Copper, aluminum and Monel 400). The engine performances and the state of each material after 15 h of use are considered. The Stainless steel was the material that best satisfies these two conditions. Five regenerators in stainless steel with different porosities were manufactured and experimented (95%, 90%, 85%, 80% and 75%). Porosity that gives the best trade-off between maximizing the engine brake power, maximizing the heat transfer and minimizing the pressure drops, was retained. Thus, the regenerator in stainless steel with porosity of 85% was considered as the most suitable matrix maximizing the Stirling engine performances and minimizing heat and friction losses.

In this paper, a linear mathematical and numerical model for analysing the dynamic response of a flexible electroactive wave energy converter is described. The Wave Energy Converter (WEC) is a floating elastic tube filled with slightly pressurised sea water. It is made of Electroactive Polymers (EAPs).Under simplifying assumptions, a set of governing equations is formulated for the flow inside the tube, the flow outside the tube and the behaviour of the tube wall. By combining them, the evolution of the flow velocity in the tube can be written as a wave equation. The corresponding eigenmodes of vibration are calculated. Then, using spectral decomposition, the equation of motion for the response of the tube in waves is derived. Experiments were carried out on a scale model of the wave energy converter in the wave tank of Ecole Centrale de Nantes in 2011. Numerical results are compared with experimental results in regular waves, showing rather good agreement, which validates the model and the initial modelling assumptions. Finally, estimates are made for the energy performance of a possible prototype.