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The aim of this research is to investigate parameters that affect the behaviour of a damaged ship and also to assess the ability of RANS codes to accurately model the physical processes occurring in the flooding of a damaged ship. Initially, the flooding of a damaged ship has been divided into smaller components to assess the accuracy of the predictions for these flow-fields when validated against experiment or other simulation methods. These components are: 1. Violent floodwater motions 2. Modelling a seaway 3. Compartment flooding rates 4. Rigid body motions
Turbomachinery Heat Transfer Analysis and Simulation
As gas turbine operating temperatures increase, thermal management methods become critical. Designing turbine blades and vanes with sufficient cooling is necessary to avoid blade damage and performance degradation. Along with the importance of knowing bulk fluid and solid temperatures, it is also important to characterize complex flow features as well as temperature uniformity and hot-spots. Additionally, blade-row interaction such as wake impingement and thermal stacking must be considered. Multi-physics analysis methods can be used in the design phase to avoid thermal management problems...
Efficient Modeling of Complex Heat Sinks Series 2 Part 1
Heat sinks are the most common heat exchange devices in electronics systems whether the system as a whole utilizes a forced—or natural—convective cooling approach. The effectiveness of the heat sink greatly depends on the material used and the geometry that can be manufactured. In the past decade, manufacturing technology advances have permitted far more complex heat sinks to be cost-effectively made in high volumes. While the increased geometric complexity provides great benefits for the overall thermal system design, the new geometries provide additional challenges to anyone performing...
Biomass to energy conversion is particularly attractive on the microscale were internal combustion engines such as microturbines may be utilized coupled to an indirect gasification system. The authors have developed the IPRP technology based on rotary kiln pyrolisys and a pilot plant was built in Italy powered by an 80 kWEl microturbine fired by pyrolysis biomass syngas. This paper describes CFD numerical investigations carried out to study the combustion process occurring inside the annular rich-quick-lean combustion chamber of the given microturbine. A RANS analysis has been performed in...
Two rectangular cavity configurations at Mach 0.85 are investigated with the objective of assessing the extent to which 3D CFD with advanced turbulence modeling is capable of predicting narrowband and broadband flow noise. A non-linear, two-equation, eddy-viscosity model run in unsteady mode (URANS) is compared with Detached Eddy Simulation (DES) on a cavity with a L/D ratio of 5, representing cavity flow in so-called shear layer mode. Detailed experimental data for this cavity, configured with and without doors, provides a valuable opportunity to compare predictions of the spectra at many...
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...

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