Search results for " CFD."
showing 10 items of 75 documents
Modeling and simulation of dense cloud dispersion in urban areas by means of computational fluid dynamics
2011
Abstract The formation of toxic heavy clouds as a result of sudden accidental releases from mobile containers, such as road tankers or railway tank cars, may occur inside urban areas so the problem arises of their consequences evaluation. Due to the semi-confined nature of the dispersion site simplified models may often be inappropriate. As an alternative, computational fluid dynamics (CFD) has the potential to provide realistic simulations even for geometrically complex scenarios since the heavy gas dispersion process is described by basic conservation equations with a reduced number of approximations. In the present work a commercial general purpose CFD code (CFX 4.4 by Ansys®) is employe…
Cross-Flow Turbine Design For Energy Production And Discharge Regulation
2015
Cross-flow turbines are very efficient and cheap turbines that allow a very good cost/benefit ratio for energy production located at the end of conduits carrying water from a water source to a tank. In this paper a new design procedure for a cross-flow turbine working with a variable flow rate is proposed. The regulation of the head immediately upstream the turbine is faced by adopting a shaped semicircular segment moving around the impeller. The maximum efficiency of the turbine is attained by setting the velocity of the particles entering the impeller at about twice the velocity of the rotating system at the impeller inlet. If energy losses along the pipe are negligible, the semicircular …
STRUCTURAL OPTIMIZATION OF INNOVATIVE RUDDER FOR HSC
2012
Currently, directional and stability control systems (rudders and flaps) of high speed craft (HSC) are made by steel box-shaped elements. This is mainly caused by the high hydrodynamic stresses applied on these elements due to the high cruising speed of HSC. In order to reduce the weight of these elements and to increase the resistance to external corrosive action, innovative manufacturing technologies and new materials are studied. In this paper, innovative hybrid steel-composite rudder are presented to use in high speed craft.
Theoretical and Experimental Comparison between the Resistance Components of a fast Catamaran in different Configurations
2009
The investigation performed by the Authors represents the most recent development of a research presented in [1] and [2], in which the geometrical solutions of the hull have been obtained through an optimization process, made by using the CFD numerical methods. The most important result of this optimization was the wave resistance reduction, which arrived up to 20% of the total initial resistance. In this further process the hull catamaran model has been built and tested at the towing tanks of the Universities of Naples and Trieste. The results obtained in the numerical process have been compared with the experimental ones and the reliability of the numerical results will be proved. Then th…
Analysis of steady state thermal-hydraulic behaviour of the DEMO Divertor cassette body cooling circuit
2017
Abstract Within the framework of the Work Package DIV 1 – “Divertor Cassette Design and Integration” of the EUROfusion action, a research campaign has been jointly carried out by ENEA and University of Palermo to investigate the thermal-hydraulic performances of the DEMO divertor cassette cooling system. A comparative evaluation study has been performed considering the two different options under consideration for the divertor cassette body coolant, namely subcooled pressurized water and helium. The research activity has been carried out following a theoretical-computational approach based on the finite volume method and adopting a qualified Computational Fluid-Dynamic (CFD) code. CFD analy…
Liberty winter gardens in Palermo: contamination from solar design
2020
At the end of the 19th century, the city of Palermo boasted a tradition of steel elements that could include the most beautiful railings and light steel structures of the time. The paper shows how the technological, formal and spatial aspects of the metallic construction was derived by the application of Central Europe areas examples to the local reality, providing notions on designs, experimentations and originalities. Canopies, verandas, winter gardens and orangeries are architectural elements in iron and glass that represent an added value for the building, they improve the life quality of the people who live there. In particular, in the Liberty architecture these elements took shape thr…
Unsteadiness and transition to turbulence in woven spacer filled channels for Membrane Distillation
2017
To characterize the performance of Membrane Distillation (MD) modules, channels filled with woven spacers were investigated by Computational Fluid Dynamics (including Direct Numerical Simulations and the use of the SST k-Ï turbulence model) and by parallel experiments with Thermochromic Liquid Crystals. The cases considered here regard mutually orthogonal filaments with a spacer pitch to channel height ratio P/H=2, two spacer orientations θ with respect to the main flow (0° and 45°), and bulk Reynolds numbers Re from â¼200 to â¼2000, an interval of great interest in practical MD applications. For both values of θ, CFD predicted steady-state flow for Re up to â¼300, and chaotic flow …
New relations between professional and work’s organizations introduced by computer applications, special vessel case study
2019
At present time the project of a naval vehicle, where with the word project we refer to all the process of design and manufacturing, especially when the vehicle offers special formal and performance characteristics, involves a number of operators that has been increasing considerably in recent decades, and this increased complexity can be correlated with dimensional and typological growth of many categories of ships. Simultaneously we are witnessing a complete new project approach, where the possibility given by the computer contribution to represent processes and results becomes crucial. The paper aims to investigate the consequences of this progress in the organization of the project and …
Large-Eddy Simulation e tecnica LS-PIV: lo studio della turbolenza superficiale
2021
Gli avanzamenti tecnologici degli ultimi decenni hanno fatto registrare la rapida diffusione di tecnologie innovative con cui condurre un monitoraggio ambientale più efficiente ed efficace. Nel campo del monitoraggio fluviale sono sempre più utilizzate le tecniche basate sull’elaborazione di immagini, fornendo una valida alternativa alle metodologie tradizionalmente adottate. Le tecniche ottiche restituiscono infatti misure non intrusive, assicurando migliori condizioni di sicurezza per gli operatori. I metodi ottici più utilizzati sono la Large-Scale Particle Image Velocimetry (LS-PIV) [1] e la Large-Scale Particle Tracking Velocimetry (LS-PTV) [2]. Le tecniche LS-PIV e LS-PTV si basano su…
STUDIO E VALIDAZIONE DI SISTEMI PER L’IDENTIFICAZIONE E IL MONITORAGGIO DI PARAMETRI BIOMEDICI ATTI ALLA PREVENZIONE DI EVENTI INDESIDERATI E ALL’ASS…
L’aumento delle patologie cronico-degenerative nella popolazione mondiale ha comportato un numero sempre maggiore di individui richiedenti assistenza sanitaria, generando, nell’ambito delle realtà ospedaliere, diverse problematiche relative al miglioramento della qualità di vita dei pazienti, ai costi e alla gestione di un numero sempre crescente di soggetti ammalati. Il trattamento sanitario e la ricerca di base si sono pertanto orientati verso la prevenzione delle condizioni che predispongono i soggetti ai peggioramenti clinici e ai ricoveri ospedalieri, puntando sia su nuovi sistemi indossabili di monitoraggio per individuare precocemente i segni di peggioramento, sia su sistemi che poss…