12,934 research outputs found
"Joyce e il cinema delle origini: Circe", by Marco Camerani
No full textThe connection between Ulysses and the seventh art has been widely discussed by scholars who have looked at the filmic interpretations of the novel or investigated the potential of film production as a form of intersemiotic translation that may serve as an analytical tool. Marco Camerani’s book adopts a reverse—albeit complementary—viewpoint and, instead of seeing cinema as the recipient of ideas and inspirations from Ulysses, focuses on the influence of cinema on Ulysses, in particular, on the “Circe” episode. Camerani is not the only author to have looked at film in Joyce rather than Joyce in film. His book, however, has two added values: on the one hand, as suggested by the title, it offers a systematized collection of the references to early movies and their structural patterns that can be traced in “Circe,” and, on the other, the volume presents the results of such research in a thoroughly enjoyable way that makes it appealing to both Joycean and film scholars, as well to a more general readership
Wind tunnel measurements for the characterization of a small scale monoplane Wells turbine
No full textIn the field of wave energy harnessing, Oscillating Water Column (OWC) devices are nowadays a consolidated technology. In OWC energy converters, waves generate an oscillating flow, whose energy can be effectively captured, for instance, by means of self-rectifying Wells turbines. In the design of Wells turbines, main issues are the improvement of their peak efficiency and the widening of their operational range. In order to reach these goals, a deep knowledge of the turbine fluid dynamic performance is essential. This paper presents the results of the experimental investigation of a small scale monoplane Wells turbine, tested in an open circuit low speed wind tunnel of the suction type in order to characterize its performance in terms of non-dimensional parameters, namely, torque and pressure drop coefficients and efficiency. The prototype under investigation, with blades of constant chord and NACA0015 profile, has been designed in order to be matched with a REWEC (Resonant Wave Energy Converter) breakwater, which had been located off the beach of Reggio Calabria. The REWEC under consideration was an excellent small scale model of full scale sea wave energy conversion devices for oceanic applications. Results have been compared with previous in-field tests, showing a very good agreement
Gas-dynamic and mixing analysis of under-expanded hydrogen jets: effect of the cross section shape
No full textGreen hydrogen is expected to have a key role in the transition towards a carbon-neutral society, particularly in the transportation sector. Exploration of novel solutions for the direct injection of hydrogen in internal combustion engines (ICEs) is a main topic for both academia and industry. Here, the authors explore the gas-dynamic and mixing features of hydrogen under-expanded jets exiting from non-axisymmetric cross-sections, with the aim to provide guidelines for designing novel generations of ICE hydrogen injectors. Triangular and star shapes have been compared with elliptical and rectangular sections with different aspect ratios. Differences in the shock wave systems are reported, and explanations of the gas-dynamic mechanisms developed by each section are proposed. Non-uniformity in the radial expansion of the jet boundary has been noticed in all of the non-axisymmetric sections, leading to an axis switching of the jet in some cases. Differences in the radial mixing and axial jet penetration have been reported too, and a robust correlation with the vorticity distribution along the jet boundary has been observed
Modello CFD per il calcolo delle prestazioni e degli effetti di scia di turbine eoliche ad asse verticale
No full textNel presente lavoro, viene proposto un metodo di calcolo fluidodinamico in grado di valutare, con ridotti tempi di calcolo, il campo di velocità in scia
e le prestazioni dei rotori Darrieus per lo studio di parchi eolici. Tale metodo potrà essere facilmente esteso al caso di turbine ad asse orizzontale.
Il metodo è validato per confronto con le prestazioni sperimentali del rotore Darrieus da 17 metri testato presso i Sandia National Laboratories
(Albuquerque) e con i risultati di altri modelli.In this work, an effective numerical technique is proposed in order to investigate flow characteristics (e.g. wakes) and performance of Darrieus rotors
in standalone configuration or included in a wind farm. This model could be easily extended to the case of horizontal axis wind turbines. The model
is validated in the case of the Sandia 17-meter Darrieus rotor tested at the Sandia National Laboratories, Albuquerque, by means of comparison with
experimental data and results from other codes
Studio teorico dell’influenza dei parametri geometrici sulle prestazioni di turbine Wells
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A new generation of centrifugal pumps for high conversion efficiency
No full textCentrifugal pumps are fundamental machines in our daily life. Indeed, they can be found everywhere, for instance, in domestic, civil, industrial, and agricultural fields. In the last years, the pump market has newly gained a boost coherently with the world demographic growth. Pumps are among the main responsible for electric energy consumption, therefore even a slight efficiency improvement (+1%) can be effective in contrasting the growth of the global Greenhouse Gas Emissions (at least −570 tCO2/day in Europe). For this reason, a new generation of centrifugal pumps is here proposed. In particular, the impeller has been redesigned improving the flow guidance inside the vanes and simultaneously reducing the number of blades, with the aim to increase the blade loading, reducing manufacturing costs, and enhancing the conversion efficiency with respect to conventional configurations. Furthermore, the new impeller design respects all the geometrical constraints of the corresponding conventional configuration, allowing its retrofit with a boost of performance. To reach these goals, a 1D in-house code has been developed implementing a Harmony Search Algorithm (HSA) for the selection of the most suitable design point (H and Q), and introducing two parameters for the blade loading evaluation, namely, the blade pressure coefficient (Cp,blade), computed locally along the impeller blade walls, and the blade lift coefficient (CL), achieving an optimal vane arrangement. Starting from a baseline centrifugal pump, the novel impeller has been designed, manufactured, and finally experimentally tested. The resulting new generation of centrifugal pumps actually proves to have a higher performance (maximum efficiency at BEP +1%), a flatter efficiency curve, and a monotone bending characteristic curve, while keeping unchanged the required Net Positive Suction Head (NPSH3%)
Performance analysis of double suction centrifugal pumps with a novel impeller configuration
No full textPumps are largely used in domestic, civil, industrial and agricultural systems. It is estimated that they are responsible of about 10% of the world energy consumption. To favor sustainability and reduce carbon footprint of pumps, it is required to improve their efficiency. In recent years, the authors proposed a novel impeller configuration (cross-vaned, with a completely new design of the vanes) for double suction centrifugal pumps with higher efficiency and reduced blade loading compared to conventional back-to-back impellers. Given the good results, herein a second version of the prototype has been designed by means of a one-dimensional (1D) in-house code with the purpose to increase the blade loading by reducing the number of blades. The new 5-bladed crossed-vaned prototype was studied numerically, then constructed and experimentally tested showing a good agreement between numerics and experiments in terms of head coefficient and efficiency. Through numerical simulations, pressure, velocity and vorticity fields at the outlet of the impeller have been investigated; besides, a new slip factor correlation is proposed for this new generation of pumps. Moreover, the new configuration confirms its benefit in term of reduction of the slip factor and increase of the global efficiency, proving to be useful for retrofitting of old impellers, with a higher efficiency and smaller overall dimensions. Finally, an example of conventional impellers retrofitting in a real pumped-storage system is presented and its impact in terms of global efficiency and carbon footprint is discussed
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