Search results for "CFD"
showing 10 items of 249 documents
Analisi fluidodinamica e sperimentale su una turbina Cross-Flow
2014
L'energia idroelettrica è una forma di energia rinnovabile che oggi sta subendo un profondo processo di trasformazione passando da un sistema centralizzato di produzione ad un sistema di tipo distribuito. Tale processo ha dato un forte impulso alla costruzione di impianti di produzione idroelettrici su piccola scala. Questi impianti si possono realizzare: 1) lungo piccoli corsi d'acqua con piccoli salti disponibili, 2) alla fine di lunghe condotte di adduzione in corrispondenza della sezione di consegna ad un serbatoio cittadino, 3) nelle reti di distribuzione idriche dove il carico piezometrico in eccesso si dissipa con valvole di regolazione, 4) a valle di impianti di depurazione nel caso…
Analyse expérimentale et numérique du comportement de véhicules terrestres en présence d'un vent latéral instationnaire
2013
The automotive manufacturers are nowadays more and more interested in crosswind aerodynamics. Indeed, the driver is subjected every day to strong side air flows, for example when overtaking another vehicle or when passing through a lateral wind wall, generated by terrain topography (as in the case of the passage near the empty space between two buildings).The aerodynamic efforts generated in these situations can lead to undesired lateral deviations,which can be dramatic if the driver is surprised. Different experimental studies, reproducing the effects of a dynamic yaw angle, pointed out the issues of the steady methods, commonly used to qualify the vehicle crosswind behaviour. Little is st…
MHD Free Convection in Helium-Cooled Lithium-Lead Blanket Modules for the Demonstration Fusion Reactor
2003
Integrated multi-physics design tool for fusion breeding blanket systems - development and validation
2020
Il Breeding Blanket (BB) del reattore DEMO rappresenta un sistema complesso in un ambiente pericoloso. Infatti, esso deve soddisfare diversi requisiti e vincoli ingegneristici sia di tipo nucleare, termo-strutturale che di sicurezza. Per questi motivi, è necessaria una progettazione omnicomprensiva che preveda l'applicazione di strumenti avanzati di simulazione basati su approcci multi-fisici. Questi strumenti devono eseguire simultaneamente diversi tipi di analisi. Tre di esse possono essere considerate prioritarie e propedeutiche per lo studio di tutti gli altri fenomeni riguardanti il BB, vale a dire l´analisi nucleare, termo-fluidodinamica e strutturale. In questa tesi, è proposto un in…
THERMOFLUID-DYNAMICS OF DEMO DIVERTOR CASSETTE
2023
The divertor is a critical in-vessel component of nuclear fusion reactors, being responsible for the fulfilment of certain fundamental functions for the machine: it must be able to handle the power deposited by charged particle and neutron irradiation, ensure the presence of channels through which the fusion ashes can be removed from the Vacuum Vessel (VV), provide plasma-compatible surfaces, and shield the VV and magnets from nuclear loads. The heat load that can be tolerated by the divertor under normal and off-normal operating conditions is a pivotal parameter when dimensioning a fusion power plant since exceptionally high heat fluxes can be observed in some regions of the divertor, in t…
Eulerian-Eulerian modelling and computational fluid dynamics simulation of wire mesh demisters in MSF plants
2014
Purpose – The purpose of this study is to focus on simulation of wire mesh demisters in multistage flash desalination (MSF) plants. The simulation is made by the use of computational fluid dynamics (CFD) software. Design/methodology/approach – A steady state and two-dimensional (2D) model was developed to simulate the demister. The model employs an Eulerian-Eulerian approach to simulate the flow of water vapor and brine droplets in the demister. The computational domain included three zones, which are the vapor space above and below the demister and the demister. The demister zone was modeled as a tube bank arrange or as a porous media. Findings – Sensitivity analysis of the model showed t…
Eulerian–Lagrangian modeling and computational fluid dynamics simulation of wire mesh demisters in MSF plants
2016
Abstract This study focuses on computational fluid dynamics model (CFD) for simulation of demisters in multistage flash desalination (MSF). The Eulerian–Lagrangian model (steady-state and two-dimensional) was developed to simulate the demister. The model was used to simulate the flow of water vapor and brine droplets in the demister. The computational domain includes the following three zones: the vapor space above the demister, the vapor space below the demister, and the demister. The demister zone was modeled as tube banks. A sensitivity analysis of the model revealed that vapor velocity is the main parameter that affects demister performance. Additionally, the analysis indicated that vap…
Heavy Gas Dispersion Modelling Over a Topographically Complex Mesoscale: A CFD Based Approach
2005
Abstract: Potentially dangerous events involving heavy gas dispersion and their severe consequences have been largely publicized by the media. Simplified models have been widely applied to describe the effects of these accidents. However, most simplified models deal with flat terrain scenarios and are based on quite crude simplifications of the complex phenomenology involved. In this paper the possibility of simulating the dispersion of heavy gas clouds over a large topographically complex area (tens of km) by a general purpose computational fluid dynamics (CFD) code is investigated. The aim is that of setting up a tool able to produce a realistic description of such dispersion processes, w…
Caractérisation et prédiction du rendement de projection lors du procédé de projection à froid – cas de la métallisation des polymères
2020
This thesis work deals with the cold spray metallization of polymer substrates by aiming at an optimal deposition efficiency using experimental analysis combined with numerical simulation. Experimental observations of the powder jet using an ombroscopic analysis have revealed a generic behavior consisting of a uniform confined zone at the immediate exit of the nozzle followed by a dispersed zone. The supersonic flow at the nozzle exit being essentially axial, the powders are entrained to form a uniform jet. Beyond a certain distance, a dispersion appears. This distance is very important because it characterizes the behavior of the powders. It can alter the conditions for the elaboration of …