Antonio Dumas

The main objective of this paper is to provide a realistic weight model, based on the physical-mathematical foundations, for the design of the new very large lighter-than-air vehicle, called Multibody Advanced Airship for Transport (MAAT), the ongoing European FP7 project, which is currently under intensive research and development activities. The Modeling and Simulation (M&S) principles, aided with simulations and visualization tools, have been extensively used, as the key enablers to combine, manage and structure such highly complex engineering process, which emerged as a natural integration mechanism and evidence provider of the encountered complexity, successfully encompassing the MAAT multidisciplinary design requirements. The authors experience, in solving the M&S problems, gained within the European R&D projects, was efficiently reused, where the use of such software technologies have been successfully demonstrated, and today, further applied for the new generation transporta...

The project aim is to achieve a lite blimp equipped to scan the spatial dispersion and thermal sources. The articulation of the research program includes the study and implementation of a system for detecting aerothermography. The tests will be carried out on urban land in the city of Reggio Emilia, these operations will make possible the detection of all the basic parameters for the operation of the system, and then to streamline the processes in place. The establishment of action research refers to the need to continue working on an integrated cognitive action by which to operate the crossing, the terms of split detection, evaluation and interpretation of the dynamics of the area and priorities / critical emerging. A second aspect concerns the intention to follow the path of deepening and study of local sustainability indicators

The advantages associated to Vertical Short-Take-Off and Landing (V/STOL) have been demonstrated since the early days of aviation, with the initial technolology being based on airships and later on helicopters and planes. Its operational advantages are enormous, being it in the field of military, humanitarian and rescue operations, or even in general aviation. Helicopters have limits in their maximum horizontal speed and classic V/STOL airplanes have problems associated with their large weight, due to the implementation of moving elements, when based on tilting rotors or turbojet vector mechanical oriented nozzles. A new alternative is proposed within the European Union Project ACHEON (Aerial Coanda High Efficiency Orienting-jet Nozzle). The project introduces a novel scheme to orient the jet that is free of moving elements. This is based on a Coanda effect nozzle supported in two fluid streams, also incorporating boundary layer plasma actuators to achieve larger deflection angles. ...

It is possible to define a novel design method, which aims overcoming both traditional, the traditional Multidisciplinary Design Optimization, and to solve a fundamental issue relating to the actual formalization of the Constructal optimization method. It aims only to enhance and integrate the constructal design method and aims to produce designs, which could be, optimized both at system level and subsystem definition. This novel method is based on the second principle of thermodynamics and the constructal law. It aims to produce a design process based on two steps. The first step aims producing a theoretical design of a system to reach energetic and operative optimization. The second aims to optimize the subcomponents of the system according the bottom up approach defined by constructal design optimization. A third step relating to the readiness against technology analysis is necessary to develop an effective industrial design. This method has named Constructal Design for Efficienc...

Many airship projects have been presented during last years. Most of them are slowed in their realization because of very high costs of Helium. This paper presents an economic and energetic comparison between Helium filled airships and Hydrogen filled ones under the hypothesis of buying 20 MPa compressed Helium and local production of photovoltaic hydrogen by electrolysis. The economic evaluation comprises the costs of PV plant for hydrogen production and docking and distribution systems for both gasses. Analysis of uncertainty has been performed to evaluate economic parameters and payback time of the investments.

ABSTRACT Export Date: 7 December 2013, Source: Scopus, References: (2004) The Urban Community of Dunkerque is Actively Pursuing a Green Energy Policy, , http://www.dunkerque2010.org/en/dunkerque-grandlittoral/ local-sustainability/energy/index.html, VV. AA;

The European project MAAT (Multi-body Advanced Airship for Transport) is producing the design of a transportation system for transport of people and goods, based on the cruiser feeder concept. This project defined novel airship concepts capable of handling safer than in the past hydrogen as a buoyant gas. In particular, it has explored novel variable shape airship concepts, which presents also intrinsic energetic advantages. It has recently conduced to the definition of an innovative design method based on the constructal principle, which applies to large transport vehicles and allows performing an effective energetic optimization and an effective optimization for the specific mission. While the traditional constructal method performs an optimization with a down-to-top approach, it produces an optimization process in two stages: the first one defines the optimal characteristics of the system understood as a unitary system to achieve the desired performances; the second analyzes the subsystems, examining those most disadvantaged, in order to optimize its performance for the desired goal. It has been deeply tested on a traditional shaped airship allowing verifying that a changing volume airship has globally better energetic performances than a fixed volume one. This paper performs a preliminary analysis of the method for the design of a cruiser/feeder multibody airship such as the one, which is going to be designed inside the MAAT project. The model presented defines the guidelines for the optimization of the system considering the magnitudes involved in flight physics to achieve the goal of energetic self-sufficiency.

This paper presents a mathematical model of the vertical forces acting on an airship during vertical motion. The main effort is the definition of an airship model, which move only vertically by ballast, and buoyancy effects, with a much reduced energy consumption for take-off and landing operations. It has been considered a disc-shaped airship, which can operate using the open balloon airship architecture defined to operate safely with hydrogen. This architecture does not require internal ballonets, because of the connected increased fire dangers that they create even if vented. Several models of airship based on vertical forces have been presented in literature. They often consider only the US or International Standard Atmosphere models and they neglect effects of weather conditions. The latter are connected with the location and with the season. These environmental and climatic factors have a large influence on behaviors of the airship system, because it is well known that the internal buoyant gas changes pressure and density condition because of external temperature. This paper defines the lifting behavior in terms of speed and acceleration. It evaluates the load factor as a function of the buoyancy and the ballast on board as a function of climatic conditions. A very simple methodology has been also presented on daily basis, authors neglect the effect of overheating of the gas due to solar radiation on the surface of the balloon, which can support the predefinition of climatic effects. The proposed methodology corrects the International Standard Atmosphere model by considering climatic data such as temperature, density and pressure of the air dependent on seasonal factors and location on annual basis

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In a previous work it has been demonstrated that solar radiation intercepted by an unconventional airship is sufficient for all energetic needs for civil uses, namely broadcasting and telecommunications. This article analyses the energetic feasibility of an airship, named PSICHE (acronym for ‘photovoltaic stratospheric isle for conversion in hydrogen as energy vector’). It demonstrates the economic and industrial feasibility of high altitude production of electrolytic hydrogen fed by a photovoltaic plant. The most important aspects connected with high quote and hydrogen and oxygen production are discussed. The advantages of this kind of hydrogen production are presented together with the environmental benefits of the system.

ABSTRACT Airships were the first air vehicles, which had the ability to generate lift without the use of aerodynamic flow around wings, also to enable controlled, powered flight, providing long endurance at low energy consumption. They were widely used before the 1940s, but their use decreased as their capabilities were exceeded by those of the airplanes. Their decline continued with a series of several accidents, including the burning of the hydrogen-filled Hindenburg, and the destruction of the USS Akron.

This paper compares hydrogen production by photovoltaic powered electrolysis of water at sea level and at low stratospheric altitudes up to 21 km. All the hydrogen production processes have been considered from catchable solar radiation to storage technologies. The evaluation has been performed for 1 m2 of flat horizontal plane. It has been considered the electric energy amount produced by considering the equilibrium temperature of photovoltaic (PV) modules and its evolution due to external temperature and solar radiation. Hydrogen production through electrolysis has been evaluated too. Two different methods of hydrogen storage have been evaluated: high pressure compression up to 20 MPa and the liquefaction process. The energetic cost of both production processes has been evaluated. The comparison is presented in terms of effective energy deliverable to final users considered in terms of HHV. This evaluation considers also, in the case of the liquefaction process the energy which ca...

ABSTRACT Cited By (since 1996):4, Export Date: 4 October 2013, Source: Scopus, doi: 10.4271/2012-01-1512, Language of Original Document: English, Correspondence Address: Trancossi, M.; Universita' di Modena e Reggio EmiliaItaly; email: michele.trancossi@unimore.it, References: European Commission (2011), 7. , http://cordis.europa.eu/wire/index.cfm?fuseaction=article.Detail&rcn=28667, MAAT Multibody Advanced Airship for Transport Project, CORDIS -Community Research and Development Information Service, November 28Dumas, A., Trancossi, M., Madonia, M., Giuliani, I., Multibody Advanced Airship for Transport (2011) SAE Technical Paper 2011-01-2786, , doi:10.4271/2011-01-2786;

This paper presents a theoretical model of Coanda attachment mechanisms and laws of the Coanda effect. In this paper, it has been considered a very conventional setup in order to define by a theoretical analysis a mathematical model of the Coanda adhesion. It has been produced a complete mathematical model which could allow simple engineering calculations through an effective solutions of the differential equations of the system. A parametric model has defined as a function of main cinematic and geometric parameters. The final model relates to three fundamental parameters: outlet section, Coanda surfaces radius and inlet velocities. Turbulent and laminar models have defined. Validation through a large CDF campaign has produced in a regime of stream velocities from 10 to 40 m/s with good results.

Purpose Aeronautic transport has an effective necessity of reducing fuel consumption and emissions to deliver efficiency and competitiveness driven by today commercial and legislative requirements. Actual aircraft configurations scenario allows envisaging the signs of a diffused technological maturity and they seem very near their limits. This scenario clearly shows the necessity of radical innovations with particular reference to propulsion systems and to aircraftarchitecture consequently. Methods This paper presents analyses and discusses a promising propulsive architecture based on an innovative nozzle, which allows realizing the selective adhesion of two impinging streams to two facing jets to two facing Coanda surfaces. This propulsion system is known with the acronym ACHEON (Aerial Coanda High Efficiency Orienting Nozzle). This paper investigates how the application of an all-electric ACHEONs propulsion system to a very traditional commuter aircraft can improve its relevant performances. This paper considers the constraints imposed by current state-of-the-art electric motors, drives, storage and conversion systems in terms of both power/energy density and performance and considers two different aircraft configurations: one using battery only and one adopting a more sophisticated hybrid cogeneration. The necessity of producing a very solid analysis has forced to limit the deflection of the jet in a very conservative range (±15°) with respect to the horizontal. This range can be surely produced also by not optimal configurations and allow minimizing the use of DBD. From the study of general flight dynamics equations of the aircraft in two-dimensional form it has been possible to determine with a high level of accuracy the advantages that ACHEON brings in terms of reduced stall speed and of reduced takeoff and landing distances. Additionally, it includes an effective energy analysis focusing on the efficiency and environmental advantages of the electric ACHEON based propulsion by assuming the today industrial grade high capacity batteries with a power density of 207 Wh/kg. Results It has been clearly demonstrated that a short flight could be possible adopting battery energy storage, and longer duration could be possible by adopting a more sophisticated cogeneration system, which is based on cogeneration from a well-known turboprop, which is mostly used in helicopter propulsion. This electric generation system can be empowered by recovering the heat and using it to increase the temperature of the jet. It is possible to transfer this considerable amount of heat to the jet by convection and direct fluid mixing. In this way, it is possible to increase the energy of the jets of an amount that allows more than recover the pressure losses in the straitening section. In this case, it is then possible to demonstrate an adequate autonomy of flight and operative range of the aircraft. The proposed architecture, which is within the limits of the most conservative results obtained, demonstrates significant additional benefits for aircraft manoeuvrability. In conclusion, this paper has presented the implantation of ACHEON on well-known traditional aircraft, verifying the suitability and effectiveness of the proposed system both in terms of endurance with a cogeneration architecture and in terms of manoeuvrability. It has demonstrated the potential of the system in terms of both takeoff and landing space requirements. Conclusions This innovation opens interesting perspectives for the future implementation of this new vector and thrust propulsion system, especially in the area of greening the aero-nautic sector. It has also demonstrated that ACHEON has the potential of renovating completely a classic old aircraft configuration such as the one of Cessna 402.

A finite difference technique is developed for evaluating the rate of heat transfer in the thermal entrance region of ducts with axial conduction. The pipe is assumed to extend from minus to plus infinity, while the velocity profile is fully developed. The boundary condition selected is a uniform heat flux for z greater than or equal to 0, while the wall temperature is kept uniform and equal to its minus infinity value for z less than 0. The results show that axial conduction and heat losses from the unheated section of the pipe significantly affect the temperature profile at the inlet of the heated part lower than the local mixed mean temperatures immediately downstream from the start of the heating. It is found that the performance of this type of heat exchanger can be described by a new parameter as an alternative to the usual Nusselt number.

This paper focuses on the key problem of future aeronautics: which relates on energy efficiency and environmental footprint on a scientific point of view. Reducing emissions and increasing the energy efficiency would be both a key element to propel the market and increase the diffusion of personal aerial transport against ground transportation. Novel vehicle concepts and systems will be necessary to propel this innovation which could revolutionize our way of moving. This paper approaches an energetic preliminary design of a vehicle concept which could fulfill this social and cultural objective. Low cost energy efficient vehicles, which could be suitable for personal use with a high economic efficiency and without needs of airports, seem actually a real dream. Otherwise, is it a feasible goal or a scientific dream? Otherwise, a design method based on first and second law and thermodynamic and constructal law could allow reaching those goals. This paper presents a preliminary design of a propulsion concept which could have the ambition and demonstrate the theoretical feasibility, using mostly existing industrial components and indicating the few ones which are not disposable today, but giving preliminary guidelines for their development.

The noise emitted by an electrical pump is mainly generated by different sources, (mechanic impacts of rotor, fluid dynamic turbulences) but it is also affected by the structural response of each component of the pump. In this paper experimental results of the acoustic characterisation of an electrical pump is presented in order to point out the influence of different noise sources to the emitted noise power. Different techniques of investigations have been performed: measurements of the acoustic field are carried out and compared with vibration response of the pump. A parallel investigation of the thermograph radiation during the start up was also performed in order to a better understanding of the localisation on noise sources.

This paper presents a novel UAS (Unmanned Aerial System) designed for excellent low speed operations and VTOL performance. This aerial vehicle concept has been designed for maximizing the advantages by of the ACHEON (Aerial Coanda High Efficiency Orienting-jet Nozzle) propulsion system, which has been studied in a European commission under 7th framework programme. This UAS concept has been named MURALS (acronym of Multifunctional Unmanned Reconnaissance Aircraft for Low-speed and STOL operation). It has been studied as a joint activity of the members of the project as an evolution of a former concept, which has been developed during 80s and 90s by Aeritalia and Capuani. It has been adapted to host an ACHEON based propulsion system. In a first embodiment, the aircraft according to the invention has a not conventional shape with a single fuselage and its primary objective is to minimize the variation of the pitching moment allowing low speed operations. The shape with convex wings has been specifically defined to allow a future possibility of enabling stealth operations. Main objective of the design activity has been focused on low speed flight, very short take off and landing, and a control possibility by mean of two mobile surfaces in the front canard, which allow changing the pitch angle, and allows an almost complete plane control in combination with an ACHEON variable angle of thrust propulsion system. The design considers has been specifically to allow flying at a speed which is lower than 12 m/s with an high angle of attach (over 7°), without losses in terms of manoeuvrability and agility. These features allow innovative uses such as road monitoring, and police support and are characterized by a breakthrough performance level. A complete optimal sizing of the aircraft has been performed, together with an effective performance analysis, which allows identifying the strong points and the potential problems of the project. An effective energy analysis has been performed also. An effective prototyping is expected in about one year.

One of the best airplanes ever realized by the European Aircraft industry was the Dornier Do 28D Skyservant, an extraordinary STOL light utility aircraft with the capability to carry up to 13 passengers. It has been a simple and rugged aircraft capable also of operating under arduous conditions and very easy and simple maintenance. The architecture of this airplane, which has operated actively for more than 20 years, is very interesting analyzing the implementation of a new propulsion system because of the unusual incorporation of two engines, as well as the two main landing gear shock struts of the faired main landing gear attached to short pylons on either side of the forward fuselage. This unconventional design allows an easy implementation of different propulsion units, such as the history of different experimental versions allowed. This paper presents the preliminary definition of an increased performance cogeneration system for optimizing the energy efficiency and maximizing the thrust of ducted fan propeller. It then produces an effective design of the ACHEON nozzle for such an aircraft, the definition of the optimal positioning for stability and efficiency. In conclusion, it analyses the expected performances of the resulting aircraft architecture. Outstanding results allows verifying an effective possibility of implementing the ACHEON Coanda effect thrust and vector propulsion system on real aircraft.

A finite difference technique is developed for evaluating the rate of heat transfer in the thermal entrance region of ducts with axial conduction. The pipe is assumed to extend from minus to plus infinity, while the velocity profile is fully developed. The boundary condition selected is a uniform heat flux for z greater than or equal to 0, while the wall temperature is kept uniform and equal to its minus infinity value for z less than 0. The results show that axial conduction and heat losses from the unheated section of the pipe significantly affect the temperature profile at the inlet of the heated part lower than the local mixed mean temperatures immediately downstream from the start of the heating. It is found that the performance of this type of heat exchanger can be described by a new parameter as an alternative to the usual Nusselt number.

Coanda effect is the adhesion of fluid on a convex surface. This paper presents the effect of temperature on the Coanda flow and shows how the temperature of the surface can influence the flow behaviour. It has been found that there are two mechanisms which influence the flow behaviour; both have contrary effect on the flow. One is based on variable Prandtl number and another is based on constant Prandtl number (thermal diffusivity) effect. The increment of the thermal diffusivity has prolonged separation of the boundary layer, while other mechanism triggers the earlier detachment of the flow from the curved surface. The preliminary CFD evaluation has provided the important controlling parameter for the thrust deflection.

ABSTRACT All manufactured products have geometrical variations which may impact their functional behavior. Tolerance analysis aims at analyzing the influence of these variations on product behavior, the goal being to evaluate the quality level of the product during its design stage. Analysis methods must verify whether specified tolerances enable the assembly and functional requirements. This paper first focuses on a literature overview of tolerance analysis methods which need to deal with a linearized model of the mechanical behavior. Secondly, the paper shows that the linearization impacts the computed quality level and thus may mislead the conclusion about the analysis. Different linearization strategies are considered, it is shown on an over-constrained mechanism in 3D that the strategy must be carefully chosen in order to not over-estimate the quality level. Finally, combining several strategies allows to define a confidence interval containing the true quality level.