<p>Agricultural tractors make massive use of hydraulic control technology. Being fuel con-sumption a big concern for agricultural applications, tractors typically use the state-of-the-art technology, load-sensing (LS) architecture, to allow good controllability in systems withmultiple actuators while promoting higher energy efficiency. Several variants of LS systemshave been proposed over the years, and research on cost-effective methods to further increasetheir efficiency is of high interest for original equipment manufacturers (OEMs) and the fluidpower community. In this work, several energy-efficient solutions are proposed and demon-strated for the reference agricultural tractor hydraulic system, aiming at reducing the fuelconsumption and increasing the system efficiency, but without affecting the functionalityof the hydraulic control system. More importantly, facing the more stringent regulationson the CO2emission and the rising consciousness of a greener environment in society, bothindustry and academia have investigated the use of electricity as energy carrier and storage.This report also carries out the study on the possibility of electrification of the referencemachine, focusing on the auxiliary hydraulic supply to the planter.</p> <p>To begin with, the quantification of the energy loss within the hydraulic system representsan important step to drive the development of cost-effective solutions. For this purpose, acombined approach of simulation and experimental testing has been undertaken to character-ize the power distribution in the high-pressure circuit. After learning that the remote controlvalves are responsible for up to 25% of power loss in the system, two different energy-efficientsolutions are proposed on the tractor circuit. Both methods target at lowering the pumpdelivery pressure through incorporating electronic proportional pressure reducing valves (ep-PRVs). To support the development of the technology, the research takes into considerationthe circuit of a 400 hp tractor, simulation and experimental results show that among themain working conditions the solution can reach up to 15.6% power saving over the standardLS system.</p> <p>Moreover, the primary purpose of a tractor is to providing power to and controllingvarious implements. Most of their mechanical actuation is performed also with the electro-hydraulic fluid power system that is highly power-dense and versatile, but that has a low energy transmission efficiency. A new control approach of the hydraulic supply units thatpower the implement functions through the hydraulic remote is proposed, which switches thetraditional flow control methodology to an impressed pressure methodology. With a 16-rowplanter connected to the tractor understudy, a simulation model of the two vehicles is imple-mented and validated against experiments. Experiments on the proposed solutions appliedto the reference tractor and planter confirmed how an overall 38% efficiency improvementwas achieved during actual tests.</p> <p>On top of the IPSC strategy, more intelligent control algorithm is explored by proposinga new system architecture to fully incorporate both of the LS pumps with all of the EHRs,to achieve dynamic regrouping control (DRC) or static regrouping control (SRC). The DRCalgorithm determines the best supply configuration to all of the functions with minimumpower loss in time, which eventually leads to 44% power reduction compared to the base-line. On the other hand, the SRC algorithm targets at providing the best planter groupinglayout when connected to the tractor supply to contribute to least throttling losses duringrepresentative planting operations. The restuls from the SRC configuration can serve as asuggestive layout for the OEM when promoting such machines to the market.</p> <p>Last but not least, different scenarios of both selective purely electrification architectureand selective e-pump supply architecture are considered to discover the potential futuredirection of electrification to follow for the reference machine. From the power saving pointof view, replacing the fertilizer and vacuum hydraulic motors with the electric ones couldlead to 72% power reduction from the engine. However, more study on the cost analysiscould be useful to balance the saving and the cost added in the system.</p>

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The Fluidized Catalytic Cracking (FCC) is known for its ability to convert refinery wastes into useful fuels such as gasoline, diesel and some lighter products such as ethylene and propylene, which are major building blocks for the polyethylene and polypropylene production. It is the most important unit of the refinery. However, changes in quality, nature of crude oil blends feedstock, environmental changes and the desire to obtain higher profitability, lead to many alternative operating conditions of the FCC riser. There are two major reactors in the FCC unit: the riser and the regenerator. The production objective of the riser is the maximisation of gasoline and diesel, but it can also be used to maximise products like propylene, butylene etc. For the regenerator, it is for regeneration of spent or deactivated catalyst. To realise these objectives, mathematical models of the riser, disengage-stripping section, cyclones and regenerator were adopted from the literature and modified, and then used on the gPROMS model builder platform to make a virtual form of the FCC unit. A new parameter estimation technique was developed in this research and used to estimate new kinetic parameters for a new six lumps kinetic model based on an industrial unit. Research outputs have resulted in the following major products’ yields: gasoline (plant; 47.31 wt% and simulation; 48.63 wt%) and diesel (plant; 18.57 wt% and simulation; 18.42 wt%) and this readily validates the new estimation methodology as well as the kinetic parameters estimated. The same methodology was used to estimate kinetic parameters for a new kinetic reaction scheme that considered propylene as a single lump. The yield of propylene was found to be 4.59 wt%, which is consistent with published data. For the first time, a Z-factor correlation analysis was used in the riser simulation to improve the hydrodynamics. It was found that different Z factor correlations predicted different riser operating pressures (90 – 279 kPa) and temperatures as well as the riser products. The Z factor correlation of Heidaryan et al. (2010a) was found to represent the condition of the riser, and depending on the catalyst-to-oil ratio, this ranges from 1.06 at the inlet of the riser to 0.92 at the exit. Optimisation was carried out to maximise gasoline, propylene in the riser and minimise CO2 in the regenerator. An increase of 4.51% gasoline, 8.93 wt.% increase in propylene as a single lump and 5.24 % reduction of carbon dioxide emission were achieved. Finally, varying the riser diameter was found to have very little effect on the yields of the riser products.

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Cette thèse porte sur l’étude et l’optimisation aérothermique d’un alterno-démarreur utilisé dans les véhicules hybrides. Ces machines produisant beaucoup plus de puissance qu’un alternateur classique, leur refroidissement est donc critique. La machine est modélisée en utilisant la méthode nodale en régime permanent qui utilise des réseaux de conductances thermiques. Pour alimenter le modèle, on utilise des corrélations issues de la littérature pour modéliser les transferts convectifs et on effectue des calculs CFD de la machine complète pour obtenir la répartition des débits. Les résultats obtenus numériquement sont ensuite validés expérimentalement à l’aide d’essais par Vélocimétrie par Images de Particules et d’essais thermiques par mesure thermocouples. Dans un deuxième temps, on couple un algorithme d’optimisation au code pour obtenir une géométrie de la machine optimale d’un point de vue thermique. La méthode retenue est l’Optimisation par Essaim Particulaire (PSO). L’optimisation se fait sur la taille des têtes de bobines, la position des ventilateurs et la section des canaux rotoriques. On obtient des géométries différentes selon les objectifs que l’on cherche à atteindre. La dernière partie de la thèse porte sur l’optimisation multi-objectifs d’un dissipateur située sur la partie électronique à l’arrière de l’alternateur : le dissipateur doit refroidir le plus possible l’électronique sans pour autant perturber l’écoulement. On étudie aussi plusieurs formes d’ailettes pour atteindre ces objectifs. / The goal of this thesis is the aero-thermal study and optimization of a starter-alternator used in hybrid cars. This kind of machines being more powerful than a regular alternator, their cooling is critical. The machine is modeled using lumped method in steady state which uses networks of thermal conductances. The inputs for the model are obtained using correlations from bibliography for the convective heat transfers and three dimensional CFD for the flow rates inside the machine. The numerical results are validated by experimental results with PIV for the fluid results and a machine fitted with thermocouples for the thermal part. In the second part, the thermal code is coupled with an optimization algorithm to obtain an optimal geometry of the machine from a thermal point of view. The method chosen is Particle Swarm Optimization (PSO). The parameters are the sizes of the end-windings, the positions of the fans and the cross section of the rotor channels. For different objectives, different optimal geometries are obtained. The last part of this work aims at the multi-objectives optimization of a heat sink located at the back of the machine. The heat sink has to be thermally efficient but should not affect the flow. Different shapes of fins are also studied.