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Gas-liquid slug flow can exert cyclic forces on pipe bends. A knowledge of the time-varying force and its distribution on the bends is highly desirable in designing the piping and piping support systems. A numerical study has been carried out to obtain an understanding of the slug flow induced forces and develop simulation models for engineering applications. The STAR-OLGA coupling has been applied to achieve a co-simulation of 3-D CFD (Computational Fluid Dynamics) and 1-D pipeline models. In the coupling model a horizontally oriented 90° bend with a diameter of 70 mm is modelled using 3-D...
The performance of a gas diffusion layer comprised of a macro porous and micro porous layer has been studied both experimentally and by numerical simulation. Experimental data at different humidification conditions have been compared to full cell, three-dimensional computational fluid dynamics calculations to validate the physical model of the cell. Local distributions of current density, electrochemical variables, temperature,and gas composition are discussed in detail. Model calculations agree well with experimental data and the solutions with and without the micro porous layer show that...
In this paper parametric analytical studies have been carried out for the geometrical optimization of dump diffusers for modern aero-gas turbine engines. Numerical studies have been carried out using SST K- turbulence model. This code solves SST k- turbulence equations using the coupled second order implicit unsteady formulation. In the numerical study, a fully implicit finite volume scheme of the compressible, Reynolds-Averaged, Navier- Stokes equations is employed. We concluded that the judicious optimization of dump diffusers is needed with respect to its geometric and fluid dynamic...
This paper aims to study numerically the influence of the number of fuel sprays in a single-cylinder diesel engine on mixing and combustion. The CFD simulations are carried out for a heavy-duty diesel engine with an 8 hole injector in the standard configuration. The fuel spray mass-flow rate was obtained from 1D-simulations and has been adjusted according to the number of nozzle holes to keep the total injected fuel mass constant. Two cases concerning the modified mass-flow rate are studied. In the first case the injection time was decreased whereas in the second case the nozzle hole diameter...
A set of through-thickness averaged equations for momentum and strain rate are derived for the problem of axi-symmetric free-surface flow within a spinning cone. The expressions are independent of the choice of constitutive law and can therefore be used for modeling the flow of a variety of materials within an industrial conical centrifuge. By assuming a through-thickness velocity profile the distribution of flow thickness and average velocity over the internal surface of the cone can be obtained. The approach has been validated for thin Newtonian viscous flow by comparison with full three-...
During the development phase of a vehicle, several thermal tests have to be conducted in order to validate the design and ensure all vehicle level functional objectives are met. Physical tests are performed both in controlled climatic drive cells and on the road at specific test sites. These tests must be done under specified conditions, since the test data is influenced by various environmental conditions and data correction methods have to be used to interpret the test results. For road trip tests, the results are influenced by several uncontrollable factors, such as ambient temperature,...
In the process of simulating the trailing edge noise of an airfoil, performing the unsteady simulations of these broadband noise sources cheaply and accurately remains a major challenge. In the present study, two different fine turbulent unsteady simulations are tested on a thin controlled diffusion airfoil at low speed and low angle of attack. The flow conditions correspond to a recent aeroacoustic experiment run in the large ECL anechoic open-jet wind-tunnel for which detailed wall pressure and wake velocity measurements are available at the same time as the far field acoustic sound. The...
Conservation of kinetic energy, while solving only for mass and momentum of incompressible flow, is first discussed in relation with the unstructured finite volume discretisations used in industrial and commercial software. LES applications are shown for a hot wall jet, a fan blade, U-bend pipe, a tube bundle and a T-pipe-junction, using local and systematic embedded grid-refinements or polyhedral cells. The conclusion suggests that ability to locally adapt the grids to the highly variable large eddy scales in complex geometries supersedes the need for higher order schemes or even elaborate...

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