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In order to assess the accuracy and validity of subchannel, system, and computational fluid dynamics codes, the Paul Scherrer Institut has participated in the OECD/NRC PSBT benchmark with the thermal-hydraulic system code TRACE5.0 developed by US NRC, the subchannel code FLICA4 developed by CEA, and the computational fluid dynamic code STAR-CD developed by CD-adapco. The PSBT benchmark consists of a series of void distribution exercises and departure from nucleate boiling exercises. The results reveal that the prediction by the subchannel code FLICA4 agrees with the experimental data...
A major goal of fuel assembly design is a reliable prediction of the critical heat flux. Development and validation of CFD methods for predicting two-phase flows and CHF conditions is subject of ongoing research at AREVA-NP. This paper deals with numerical modeling of subcooled flow boiling of water in pipes and subchannels at flow conditions corresponding to the range of pressurized water reactor operation conditions. As simulation tool the commercial CFD software Star-CD is used in conjunction with its Extended Boiling Framework (EBF), a software package providing modeling tools for two-...
One of the major concerns of the gas diffusion layer (GDL) inside a proton exchange membrane fuel cell (PEMFC) is water management.Treatment of the pores of the GDL can affect the PEMFC performance due to the degree of water flooding inside the GDL. In this work, GDL flooding was investigated using a simplified approach in an established numerical model. The predictions are compared with experimental data of GDLs with different treatments. Local distributions inside the cell are given and the effect of homogenous GDL flooding on these is discussed.
A muffler or silencer is an integral part of the exhaust system and is a device used to prevent sound from reaching the openings of the exhaust duct and radiating as far field noise. Different acoustical design and analysis techniques are used to predict the acoustical performance of exhaust systems. Flow noise from exhaust tail pipe is one of the major noise sources in a vehicle. Flow noise is generated mainly during fast acceleration operating condition due to complex flow behavior. In this paper, we have studied the detailed flow field and tried to establish an analyses procedure for flow...
Aerodynamic computational fluid dynamics analysis of a wing glove attached to one wing of a business jet is presented and discussed. A wing glove placed on only one wing will produce asymmetric aerodynamic effects that will result in overall changes in the forces and moments acting on the aircraft. These changes, referred to as deltas, need to be determined and quantified to ensure that the wing glove does not have a significant effect on the aircraft flight characteristics. TRANAIR (Calmar Research Corporation, Cato, New York), a nonlinear full potential solver, and Star-CCM+ (CD-adapco,...
Fuel cells are an appealing alternative to fossil fuels as they operate on hydrogen fuel without any toxic byproducts. A major drawback is the reliability and durability of the bipolar plates. In this project, the bipolar plates and the Gas Diffusion Layer (GDL) were studied and the flow fields optimized using Computational Fluid Dynamics. The flow geometries of the bipolar plate on the cathode side of the fuel cell were studied to understand the impact on fuel cell performance. Steadystate, three-dimensional, laminar, isothermal, and segregated models were chosen to study the designs, while...
In recent years the use of computational simulation tools for combustion research has appeared as a way to reduce time and cost in engine research. These tools face important challenges due to the complexity of the composition of the hydrocarbon petroleum fuels. One of the solutions to this problem is the use of surrogate fuels, with known physical and chemical properties and combustion characteristics similar to real fuels. This paper presents experimental and modelling studies of auto-ignition for long-chain hydrocarbon fuels such as dodecane and hexadecane. Results show a very good...
The use of energetic nanoparticles offers a promising means of adjusting the reactivity of liquid fuels for enhanced combustion stability in next generation propulsion systems. This work outlines the development of a novel aerosol rapid compression machine (RCM) for studying the impact of energetic nanoparticles on reducing the ignition delay of liquid fuels, and a proof-of-concept demonstration is presented using ethanol and JP-8. Fuel droplets are generated using an ultrasonic nozzle. The seeding of 50 nm aluminum nanoparticles in the liquid fuel is achieved by using a combination of...
Results from numerical simulations of the NASA trapezoidal wing geometry using the unstructured finite-volume-based solver STAR-CCM+ are presented. General polyhedral meshes are generated using automated techniques that are amenable to rapid grid generation for industrial use. A steady-state RANS approach is employed using the SST k-ω turbulence model coupled with a predictive laminar-to-turbulent transition model. Results are compared to experimental measurements provided as part of the 1st AIAA High-Lift Prediction Workshop (HiLiftPW-1), both with and without slat/flap support brackets.
Alenia Aeronautica is pursuing the virtual prototyping roadmap as a fundamental brick of the Product Lifecycle Management (PLM) approach. The key issues foreseen in this context are related to multi-disciplinary optimization, system engineering and experimental platform integration. The simulation architecture relies on Computer Aided Engineering technologies where CD-adapco provides the standard for internal fluid-dynamics and thermal transmission. This capability is enhanced by the links to the remaining environment, in order to build complex infrastructures and methodologies aimed at the...

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