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The paper presents the results of preliminary investigation of the effectiveness of using the vortex generators for improving the wake flow of large merchant ships. The idea of vortex generators is based on that from aerospace industry, where the vortex generators are used to prevent the flow separation on the suction side of the airplane’s wing – the vortices introduced to the boundary layer are attaching to the wing surface. It is expected that it is also possible to take advantage of this effect in ship design, by reducing the boundary layer thickness and reducing the areas of separated...
Mixing and separation of materials in multiphase flows are extremely common and frequent operations in chemical and process engineering. For example, stirred reactor is used to give good mixing and uniform dispersion of catalyst particles in the reactor to ensure uniform quality product is produced. At the end of the process, the catalyst particles may need to be recovered and removed from the product by separation equipment such as a settling tank. The commonly asked questions by plant operators in relation to these processes are: (a) What is the optimum rotating speed should be set for the...
In this thesis a numerical model for predicting areas with high risk of corrosion in biomass fired boilers has been developed. The model was developed through a literature study and tested in a full scale CFD analysis of the second boiler at Verdo heat and power plant. STAR-CCM+ was used for the CFD calculations. The model is based on the metal temperature of heat transfer surfaces in the boiler and the concentrations of potassium chloride(KCl) and oxygen(O2). A series of preliminary analyses of the used models were conducted in order to validate the simulation of the combustion processes...
This project is one component of a broader effort whose ultimate goal is to provide CFD-based tools that can be used to optimize the design of urea SCR NOx aftertreatment systems for heavy-duty diesel engines. Here the focus is on predicting the distributions of key chemical species (ammonia, in particular) at the inlet to the catalysts. Two aspects of the physical models have been emphasized: the multi-phase models, and the gas-phase chemistry models. A hierarchy of four simplified geometric configurations has been used for model development and parametric studies, and to establish the...
In this study, we use CFD simulations to model a fully nonlinear water wave tank. Firstly, for validation purpose, regular waveswith different wave steepness are simulated and the results are compared with the second-order potential flow solution for the free surface displacement time history at fixed locations, the instantaneous free surface spatial profiles, and the velocity and pressure fields under the free surface. It is shown that for small wavesteepness, the CFD solutions agree very well with the second-orderpotential flow solutions while for large wave steepness, apparent differences...
Three-dimensional computational fluid dynamics (CFD) method was used to model the boiling two-phase flow in one of the PSBT 5-by-5 rod bundle tests. The rod bundle with all the spacers was modeled explicitly using unstructured computational grids. The “six-equation, two-fluid model” with the wall boiling model were used to model the boiling two-phase flows in the bundle. The computed void fractions compare well with the measured data at the measuring plane. In addition to the averaged void data, the CFD results give a very detailed picture of the flow and void distributions in the bundle and...
Unsteady numerical simulations of air flow, mixed with micron particles, through a human lung conducting zone during inhalation have been performed. The process included importing images from a high resolution CT-Scan into a CFD software, generation of the CFD model and then CFD simulation over a 4 seconds cycle (2 seconds for inhalation and 2 seconds for exhalation). The inlet diameter was 11 mm and the flow rates were 5, 7.5, and 15 liters/ min. Only results for the highest flow rate are presented. The implicit-unsteady Reynolds Average Navier-Stokes equations with the Wilcox K-ω turbulence...
The vehicle windshield defogging performance has direct influence under driver safety. In extreme situations, when the vehicle is not equipped with air conditioner and loaded with maximum occupancy, the defroster system must correctly direct the flow in order to defog pre-defined regions on the windshield. This process can't take too long and must guarantee a minimum fog-free area to increase driver's visibility. The main objective of this paper is to demonstrate the defogging simulation methodology developed by FIAT Brazil and Multicorpos Engineering. It uses CFD simulations with STAR-CCM+...
This paper presents the CFD modeling methodology and validation for steady-state, normal operation in a PWR fuel assembly. This work is part of a program that is developing a CFD methodology for modeling and predicting single-phase and two-phase flow conditions downstream of structural grids that have mixing devices. The purpose of the mixing devices (mixing vanes in this case) is to increase turbulence and improve heat transfer characteristics of the fuel assembly. The detailed CFD modeling methodology for single-phase flow conditions in PWR fuel assemblies was developed using the STAR-CD...
The commercial CFD code STAR-CD 4.02 is used as a numerical simulation tool for flows in the supercritical water-cooled nuclear reactor (SCWR). The basic heat transfer element in the reactor core can be considered as round tubes and tube bundles. Reactors with vertical or horizontal flow in the core can be found. In vertically oriented core, symmetric characters of flow and heat transfer can be found and two-dimensional analyses are often performed. However, in horizontally oriented core the flow and heat transfer are fully three-dimensional due to the buoyancy effect. In this paper,...

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