14th International Conference on Turbochargers and Turbocharging

14th International Conference on Turbochargers and Turbocharging addresses current and novel turbocharging system choices and components with a renewed emphasis to address the challenges posed by emission regulations and market trends. The contributions focus on the development of air management solutions and waste heat recovery ideas to support thermal propulsion systems leading to high thermal efficiency and low exhaust emissions. These can be in the form of internal combustion engines or other propulsion technologies (eg. Fuel cell) in both direct drive and hybridised configuration. 14th International Conference on Turbochargers and Turbocharging also provides a particular focus on turbochargers, superchargers, waste heat recovery turbines and related air managements components in both electrical and mechanical forms

Modelling and Optimisation of Heat Exchanger Integrated in Fan Coil Unit

The Fan Coil Unit (FCU) is an integral part of heating, ventilation and air conditioning systems used in residential and commercial buildings. One main component of this device is a multi-tube and fin heat exchanger. Improvement of thermal performance in such heat exchangers is vital for improved performance of FCU. Performance improvements in the FCUs are mainly limited by available technology, manufacturing capabilities and overall cost effectiveness of the design. Better thermal performance usually comes at a cost of higher pressure drop or more expensive materials and manufacturing costs. In this thesis, a global framework for design and optimisation was developed taking into account overall costs of design, manufacturing and operation. Full 3D CFD models of multi-tube and fins heat exchanger were developed to investigate complex and non-uniform flow on water and air sides of the device. The CFD models were developed to enable local heat transfer analysis within the FCU. Experimental setup to evaluate performance of the heat exchanger has been designed and built. Different configurations of heat exchanger were tested experimentally and numerically, including the baseline configuration, so called plain fins. More efficient design of louvre fins and and fins with vortex generating mechanism (perforation in the fin surfaces) were also investigated. Best thermal performance was found to be for the perforated louvre fins. CFD model was validated against experimental results and obtained data was used to create a novel semi-analytical prediction model for Fanning friction factor (f) and Colburn factor (j). Appropriate costs calculation model was also developed and employed for total costs estimation of the FCU over the period of 15 years. The framework proposed in this thesis for optimised design and development strategy of heat exchangers resulted in development of a novel design which offers significant improvements in comparison to the current design. This new optimised design of the heat exchanger (with perforation in louvre fins) increased thermal performance by additional 10% while the total costs increased by only 6%

Methodology for sizing and optimising a Blended Wing-Body with distributed electric ducted fans

The increase of air traffic in the last decades and its projections pose a key challenge towards the carbon neutral growth objective. To cope with this societal goal, there is a need for disruptive air transport aircraft concepts featuring new technologies with low environmental impact. Such future air vehicle relies on the various interactions between systems, disciplines and components. This Ph.D. research thus focuses on the development of a methodology dedicated to the exploration and performance evaluation of unconventional configurations using innovative propulsion concepts. The use case to be considered is the optimisation at conceptual level of a Blended Wing-Body with distributed electric propulsion, a promising concept which combines high aerodynamic performances and benefits from electric propulsion. The optimisation process based on FAST, the ISAE-SUPAERO / ONERA aircraft sizing tool, has been implemented within OpenMDAO, the NASA open-source multidisciplinary analysis and optimisation framework. With the idea of a progressive enhancement of the multidisciplinary design analysis and a better capture of the different effects, the two pioneering elements have been studied separately. First, the classical process has been revised to take into account the new hybrid powerplant. Second, a methodology has been revised to consider a radically new airframe design. Last, a design process featuring both innovative aspects has been developed to investigate a Blended Wing Body concept with distributed electric propulsion. Concerning the design process, results show that the use of gradients in the optimisation procedure speeds up the process against a gradient-free method up to 70%. This is an important gain in time that facilitates designer’s tasks. For the disruptive concept performances, results have been compared to the ones obtained for a conventional A320 type aircraft based on the same top level requirements and technological horizon. Overall, the hybrid electric propulsion concept is interesting as it allows zero emissions for Landing/Take-Off operations, improving the environmental footprint of the aircraft: fuel can be saved for missions below a certain range. This limitation is associated to the presence of batteries: indeed they introduce indeed a relevant penalty in weight that cannot be countered by benefits of electrification for longer range. Additional simulations indicate that a Blended Wing-Body concept based on a turbo-electric only architecture is constantly performing better than the baseline within the limits of the assumptions

Design of a swept-wing High-Altitude Long-Endurance Unmanned Air Vehicle (HALE UAV)

High-altitude aircraft flying in the stratosphere (around 17-30 km altitude) can provide a useful platform for sensors to support a range of military and civilian surveillance tasks. The main topic of the thesis concerns the analysis of solar powered unmanned aerial vehicles designed for extended flight operations at high altitudes. An aft-swept flying wing configuration has been adopted for high altitude applications. Specific topics that were considered focussed on the development of a conceptual design tool and a multi-disciplinary optimisation tool able to converge on the layout for a solar powered HALE UAV. A true aft-swept flying wing is perhaps the most aerodynamically efficient aircraft configuration but, to date, has not been investigated in any detail for possible application to high-altitude UAVs. Such a configuration would require a moderate amount of wing sweep in order to generate the necessary stability in flight and to provide adequate control power for manoeuvring purposes. All systems and elements can now be placed inside the wing without compromising the weight distribution. This avoids the need for drag inducing mass balancing pods and/or reflexed trailing edge associated with unswept (straight) flying wings. Such features can either increase structural weight and/or overall drag whilst reducing the maximum lift that can be achieved. However, the design, in common with the other more conventional aircraft, represents a substantial challenge due to the simultaneous addressing of numerous inter-related engineering disciplines required for a fairly comprehensive analysis. The innovative aspect of this study was dedicated to the conceptual and preliminary design of a high altitude long endurance solar powered aft-swept flying wing and study in detail the design challenges along with the general problems associated with flying at high altitudes. Moreover, these aims were achieved by the author developing new design tools. The conceptual design tool was created to include all the aircraft elements and the expected power losses in addition to representing the drag estimation of the wing section rather than using a general expression as only a function of Reynolds number regardless the aerofoil performance. The preliminary design tool, also written by the author, represented by the composite structure model and the quasi 3D aerodynamic solver combined in a multidisciplinary optimisation framework, proved its capability in determining the aircraft geometry, its weight and its aerodynamic and structural performance capabilities

12th EASN International Conference on "Innovation in Aviation & Space for opening New Horizons"

Epoxy resins show a combination of thermal stability, good mechanical performance, and durability, which make these materials suitable for many applications in the Aerospace industry. Different types of curing agents can be utilized for curing epoxy systems. The use of aliphatic amines as curing agent is preferable over the toxic aromatic ones, though their incorporation increases the flammability of the resin. Recently, we have developed different hybrid strategies, where the sol-gel technique has been exploited in combination with two DOPO-based flame retardants and other synergists or the use of humic acid and ammonium polyphosphate to achieve non-dripping V-0 classification in UL 94 vertical flame spread tests, with low phosphorous loadings (e.g., 1-2 wt%). These strategies improved the flame retardancy of the epoxy matrix, without any detrimental impact on the mechanical and thermal properties of the composites. Finally, the formation of a hybrid silica-epoxy network accounted for the establishment of tailored interphases, due to a better dispersion of more polar additives in the hydrophobic resin

New methodologies for calculation of flight parameters on reduced scale wings models in wind tunnel

In order to improve the qualities of wind tunnel tests, and the tools used to perform aerodynamic tests on aircraft wings in the wind tunnel, new methodologies were developed and tested on rigid and flexible wings models. A flexible wing concept is consists in replacing a portion (lower and/or upper) of the skin with another flexible portion whose shape can be changed using an actuation system installed inside of the wing. The main purpose of this concept is to improve the aerodynamic performance of the aircraft, and especially to reduce the fuel consumption of the airplane. Numerical and experimental analyses were conducted to develop and test the methodologies proposed in this thesis. To control the flow inside the test sections of the Price-Païdoussis wind tunnel of LARCASE, numerical and experimental analyses were performed. Computational fluid dynamics calculations have been made in order to obtain a database used to develop a new hybrid methodology for wind tunnel calibration. This approach allows controlling the flow in the test section of the Price-Païdoussis wind tunnel. For the fast determination of aerodynamic parameters, new hybrid methodologies were proposed. These methodologies were used to control flight parameters by the calculation of the drag, lift and pitching moment coefficients and by the calculation of the pressure distribution around an airfoil. These aerodynamic coefficients were calculated from the known airflow conditions such as angles of attack, the mach and the Reynolds numbers. In order to modify the shape of the wing skin, electric actuators were installed inside the wing to get the desired shape. These deformations provide optimal profiles according to different flight conditions in order to reduce the fuel consumption. A controller based on neural networks was implemented to obtain desired displacement actuators. A metaheuristic algorithm was used in hybridization with neural networks, and support vector machine approaches and their combination was optimized, and very good results were obtained in a reduced computing time. The validation of the obtained results has been made using numerical data obtained by the XFoil code, and also by the Fluent code. The results obtained using the méthodologies presented in this thesis have been validated with experimental data obtained using the subsonic Price-Païdoussis blow down wind tunnel

SOLID-SHELL FINITE ELEMENT MODELS FOR EXPLICIT SIMULATIONS OF CRACK PROPAGATION IN THIN STRUCTURES

Crack propagation in thin shell structures due to cutting is conveniently simulated using explicit finite element approaches, in view of the high nonlinearity of the problem. Solidshell elements are usually preferred for the discretization in the presence of complex material behavior and degradation phenomena such as delamination, since they allow for a correct representation of the thickness geometry. However, in solid-shell elements the small thickness leads to a very high maximum eigenfrequency, which imply very small stable time-steps. A new selective mass scaling technique is proposed to increase the time-step size without affecting accuracy. New ”directional” cohesive interface elements are used in conjunction with selective mass scaling to account for the interaction with a sharp blade in cutting processes of thin ductile shells