Search results for " CFD."
showing 10 items of 75 documents
FLUID MECHANICS ANALYSIS OF A SAILBOAT MAST
2009
This study aims to analyze different configurations of mast-sail coupling of a boat with single sail and wishbone rig to vary the shape of the cross-section of the mast that is to assess the influence of the mast on the performance of the sail. The analysis is performed with four several shapes of the mast cross section and several angles of attack to the wind. The numerical simulations on different geometries show an improvement by using a wing shape for the mast rotated in the direction of the wind, in all the corners. This solution allows to rotate rigidly the system mast-boom-sail in order to maintain the same angle of incidence and maximize the efficiency of the sail. The efficiency in…
Progettazione e Confronto di Barche a Vela Mediante Analisi CFD
2010
Le simulazioni fluidodinamiche computazionali (CFD) forniscono uno strumento particolarmente utile alla valutazione delle caratteristiche di barche a vela. La possibilità di studiare differenti carene e piani velici, ha permesso di mettere a punto geometrie che senza l’ausilio di queste tecniche innovative sarebbero apparse difficilmente raggiungibili. Nel presente lavoro sono state messe a confronto due barche a vela progettate e costruite per partecipare alle regate di Mille e una Vela per l’Università – manifestazione didattico/sportiva organizzata dall’Università Roma Tre.
ANALISI CFD DELLE PRESTAZIONI DI UN CATAMARANO CON SCAFI ASIMMETRICI DOTATO DI SOSTENTAMENTO IDRODINAMICO
2010
Nel presente lavoro è proposto uno studio di ottimizzazione su di un catamarano a scafi asimmetrici con murate piane esterne, grazie al progetto di due alettoni posizionati trasversalmente alla direzione del moto al di sotto del piano di galleggiamento ai quali è affidato il sostentamento idrodinamico dell’intero catamarano. L’obiettivo finale dello studio è quello di ridurre la resistenza totale all’avanzamento del catamarano dopo aver progettato in maniera opportuna le due appendici alari. Le analisi CFD, sia del catamarano senza alettoni che del catamarano con agli alettoni, hanno dato la possibilità di operare un confronto tra i due catamarani evidenziando un beneficio del 38% in termin…
RILIEVO FOTOGRAMMETRICO E ANALISI CFD DI COPPIE GENOA RANDA E CONFRONTO TRA FLYING SHAPE E DESIGN SHAPE
2011
Le vele di una imbarcazione sono sottoposte a grandi spostamenti a causa della loro natura altamente flessibile, per tale motivo, la forma che assumono quando sono sottoposte alla forza del vento è differente da quella di progetto stabilita dal velaio. Nel lavoro gli autori propongono un metodo basato sull’utilizzo della tecnica fotogrammetrica per il rilievo in navigazione di vele in vera grandezza. L’utilizzo di tecniche ottiche di Reverse Engineering consente, infatti, la ricostruzione tridimensionale del modello dell’intera vela. Vengono costruiti i modelli CAD delle vele di un’imbarcazione di classe Meteor in condizioni di navigazione (flying shape) e in condizioni di progetto (design …
Coupling CFD simulation with a simplified process model for reverse electrodialysis units
2017
Salinity gradient between two solutions is a renewable source of energy. Among the technologies able to exploit the salinity gradient, reverse electrodialysis (RED) is an electrochemical process for electrical power generation through direct conversion. Ion exchange membranes, piled alternately and separated by net spacers or membrane profiles, are the key elements of a RED stack. A multiplex phenomenology occurs in RED units; Ohmic and non-Ohmic (due to concentration changes) voltage losses and pressure drop are the main issues, and the membrane/channel configuration is crucial for the stack performance. In this framework, mathematical modelling can be a powerful tool for predictive purpos…
Experiments and modelling for determining the Limiting Current Density in Electrodialysis units
2018
In the present work, in order to explore such issues on the LCD identification, we performed in-situ measurements with ED units, assessing the influence of operating conditions and validating a purposely implemented process simulator, which was then used for further investigation
CFD PREDICTION OF BUBBLES BEHAVIOUR IN 2-DIMENSIONAL GAS-SOLID FLUIDIZED BEDS
2008
In recent years the use of Computational Fluid Dynamics (CFD) is significantly increasing to simulate multi-phase flows. It is invariably emphasized that a necessary step towards the development of reliable fully predictive CFD models is an extensive experimental validation of the simulation results. This work in particular focuses on the CFD simulation of a lab-scale 2D fluidized bed and the relevant experiments, in order to validate the prediction capability of the used codes and models. It must be emphasized that both experimental and computational quantitative data have been obtained by means of an original Digital Image Analysis Technique, that allows coherent comparison of computation…
Pressure drop at low reynolds numbers in woven-spacer-filled channels for membrane processes: CFD prediction and experimental validation
2017
The energy consumption due to pumping power is a crucial issue in membrane processes. Spacers provide mechanical stability and promote mixing, yet increasing pressure drop. Woven spacers and their behaviour at low Reynolds numbers are less studied in the literature. Nevertheless, they are typical of some membrane technologies, as reverse electrodialysis (RED). RED is a promising technology for electric power generation by the chemical potential difference of two salt solutions within a stack equipped by selective ion-exchange membranes. The mechanical energy required for pumping the feed solutions, can dramatically reduce the net power output. In this work computational fluid dynamics (CFD)…
Modelling Turbulent Inter-Phase Drag in Mechanically Stirred Solid-Liquid Suspensions
2012
Application of computational fluid dynamics technique in membrane distillation processes
2022
This Chapter illustrates the application of CFD to spacer-filled channels for membrane distillation. The topics discussed cover finite volume grids and grid independence, the unit-cell treatment of spatially periodic net spacers, and the dependence of flow and thermal fields and overall performance parameters (pressure drop and mean heat transfer coefficients) upon geometry and operating conditions (Reynolds number, flow attack angle, pitch-to-height ratio, spacer thermal conductivity, thermal boundary conditions, and one-side vs. two-side heat transfer).