Search results for "cfd"
showing 10 items of 249 documents
Modelling and simulation of gas-liquid hydrodynamics in mechnically stirred tanks
2007
Abstract Computational fuid dynamics (CFD) is an increasingly important tool for carrying out realistic simulations of process equipment. In the case of multiphase systems the development of CFD models is less advanced than for single-phase systems. In the present work CFD simulations of gas–liquid stirred tanks are reported. An Eulerian–Eulerian multi-fluid approach is used in conjunction with the simplest two-phase extension of the k–ɛ turbulence model. All bubbles are assumed to share the same size. The effect of inter-phase forces on simulation results is separately considered. As concerns drag, it is shown that the sole parameter needed to characterize the dispersed phase behaviour is …
Thermal-hydraulic behaviour of the DEMO divertor plasma facing components 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 three different options for the cooling circuit layout of the divertor Plasma Facing Components (PFCs). The potential improvement in the thermal-hydraulic performance of the cooling system, to be achieved by modifying cooling circuit layout, has been also assessed and discussed in terms of optimization strategy. The research acti…
Etude numérique du comportement thermique d’un séchoir solaire utilisant un lit thermique pour le stockage d’énergie
2018
This thesis presents a numerical study of an indirect natural convection solar dryer for drying agricultural products (Figs). The first part analyzes a solar dryer containing a drying chamber coupled to a reversed absorber and a solar chimney. Simulations were made to determine the dynamic and thermal fields under the influence of the variation of the solar chimney configuration and the size of the inlet opening. The governing equations based on the standard k-ε turbulence model are solved by the finite volume method using the ANSYS-Fluent commercial code. The second part analyzes the effect of adding a thermal storage in the form of a gravel bed in the drying chamber. The bed is modeled as…
ANALISI STRUTTURALE DI UN TIMONE PER ALISCAFI
2012
Attualmente i sistemi di controllo direzionale (timone) e di stabilità (flap) dei battelli veloci per il trasporto passeggeri (HSC) sono realizzati con elementi scatolari in acciaio. Ciò è essenzialmente dovuto alle notevoli sollecitazioni idrodinamiche che tali elementi sopportano a causa dell’elevata velocità di crociera. L’esigenza di ridurre il peso di tali elementi e di aumentarne la resistenza alle azioni corrosive esterne spinge ad una ricerca su materiali e tecnologie di fabbricazioni innovative. In questo studio è presentato il progetto di un timone, realizzato in materiale ibrido composito e acciaio, da impiegare su un battello per trasporto veloce passeggeri.
Analisi e sviluppo di imbarcazioni a sostentamento idrodinamico
Large-eddy simulations of turbulent flow with heat transfer in simple and complex geometries using Harwell-FLOW3D
1996
Abstract Large-eddy simulation (LES) results are presented and discussed for the turbulent flow with heat transfer in different geometrical configurations, including a plane channel, a channel bearing transverse square ribs on one of the walls, and a crossed-corrugated air heater. They were obtained using the computational fluid dynamics (CFD) code Harwell-FLOW3D (Release 2), finite-volume grids having up to 423 nodes, and the Smagorinsky subgrid model with several variants regarding near-wall damping and wall boundary conditions. The first problem (plane turbulent Poiseuille flow with heat transfer) was mainly used as a benchmark to investigate the influence of numerical methods (pressure-…
Modelling wet-air oxidation of phenol in a trickle-bed reactor using active carbon as a catalyst
2016
A SIMULTANEOUS ENGINEERING APPROACH TO THE YACHT DESIGN
2009
The authors describe the approach applied to the design and manufacturing of a 15” dinghy which will challenge other similar sailing boats in fleet regattas. The Simultaneous Engineering approach appears to be the most powerful instrument since it permits to keep under control many variables simultaneously and then to reduce the Time To Market. Starting from regatta rules and limitations, the hull shape has been chosen and then modelled with a parametric CAD software. Such a model has been managed in order to be suitable for both FEM (Finite Element Method) and CFD (Computational Fluid Dynamics) analyses.
Optimal control in models with conductive‐radiative heat transfer
2003
In this paper an optimal control problem for the elliptic boundary value problem with nonlocal boundary conditions is considered. It is shown that the weak solutions of the boundary value problem depend smoothly on the control parameter and that the cost functional of the optimal control problem is Frechet differentiable with respect to the control parameter. Optimalus valdymas modeliuose su laidžiu-radioaktyviu šilumos pernešimu Santrauka Darbe nagrinejamas nelokalaus kraštinio uždavinio optimalaus valdymo uždavinys. Parodyta, kad silpnasis kraštinio uždavinio sprendinys tolydžiai priklauso nuo valdomojo parametro, taigi, optimalaus valdymo tikslo funkcija yra diferencijuojama Freše prasme…