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Successful transcatheter aortic valve (TAV) deployment and function are heavily reliant on the implant-host tissue interaction. Many adverse events observed clinically in TAV procedures such as impairment of coronary artery flow, paravalvular leak, and access site injury could be attributed to improper TAV deployment and interaction with the aortic root. In this study, we performed a computational analysis of the TAV-aortic root interaction, particularly the hemodynamics before and after TAV deployment. Utilizing a recently developed computational TAV model, we simulated the deployment of...
Subsea jumpers are steel pipe sections that connect hardware components on the seafloor (e.g. trees, manifolds, and sleds) and typically operate in multi-phase flow. They are designed with bends to accommodate limited expansion due to variations in temperature and pressure. Under certain conditions significant fluctuating forces can be induced in flow-turning elements like bends and tees. These fluctuating forces may cause severe piping vibrations and weld fatigue damage. This paper presents a flow-induced vibration screening procedure based on the 3-D numerical simulation of unsteady...
The purpose of the present study is to evaluate the feasibility of use of CFD Large Eddy Simulation (LES) modeling techniques in CD-adapco CFD code STAR-CCM+ to calculate the instantaneous stress tensor on the fuel rod wall and then utilize these data for mechanical calculations. Transient hydraulic forces on the fuel rod resulting from the CFD model are linked to the Westinghouse VITRAN code to predict fuel rod vibration response. The coupled CFD/mechanical solution has provided a reasonable prediction of fuel rod vibration and a more accurate representation of all the important physics and...
This thesis is a study of the aerodynamics of a generic model of the Apache wingsuit subjected to angle displacements at high velocity. The Apache wingsuit is a wing equipped jumpsuit, used to enhance the experience of skydiving by producing glide capability. The origin of this case is from an event were unstable behaviour was experienced by the pilot when a dive at 83 m/s (~300 km/h) was followed by an increase of angle of attack which triggered the incident. Aerodynamics regards a big number of phenomena. Many studies have been done on airplanes but not many on wingsuits and an important...
A finite volume method-based CFD model has been developed in the commercial code STAR-CD to simulate the annular gas-liquid flow through the 30°, 60° and 90° bends. The liquid film is solved explicitly by means of a modified Volume of Fluid (VOF) method. The droplets are traced using a Lagrangian technique. The film to droplets (entrainment) and droplets to film (stick, bounce, spread and splash) interactions are taken into account using sub-models to complement the VOF model. A good agreement is found between the computed film thickness value and those cited in the literature.
The aim of the present work is to choose an optimal method for thermohydraulic calculation of the gas flow in channels with intense heating at the flow Reynolds number below 10,000. These conditions are typical of the cooling channels of the High-Flux-Test Module of the International-Fusion-Materials-Irradiation-Facility (IFMIF/HFTM). A low Reynolds number and a high heating rate can result in partial relaminarization of the initially turbulent flow, and hence in a decrease in the heat transfer. A number of turbulence models offered by the commercial STAR-CD code were tested on the basis of...
Fast reactors are being considered as one element of future nuclear power systems to enable continued use and growth of nuclear power by limiting high-level waste generation. However, their higher cost relative to existing nuclear reactor designs, even with their higher thermal efficiency, results in higher electricity costs making them economically less attractive to nuclear utilities. In an effort to increase thermal efficiency, fuel subassembly design changes are being investigated using computational fluid dynamics simulations. The goal of this study is to evaluate the effects that...
In this report, We compared the actual test with the result of POW calculation and Resistance/Self-propulsion of the ship using STAR-CCM+ which is the commercial Reynolds Averaged Navier-Strokes(RANs) Solver. The calculation model was the KRISO Container Ship and 205K Bulk Carrier of Sungdong shipbuilding company. For this calculation, We used Realizable K-Epsilon model for flow analysis, VOF method for the free surface creation, Moving Reference Frame method for reducing the POW calculation time, and Sliding Mesh method for Self-Propulsion analysis. Calculation of Resistance and Self-...
Thelean stability limit of a prototype syngas burner is investigated.The burner is a three sector system, consisting of aseparate igniter, stabilizer and Main burner. The ignition sector, Rich-Pilot-Lean(RPL), can be operated with both rich or lean equivalencevalues, and serves to ignite the Pilot sector which stabilizesthe Main combustion sector. The RPL and Main sectors arefully premixed, while the Pilot sector is partially premixed. Thecomplexity of this burner design, especially the ability to varyequivalence ratios in all three sectors, allows for the burnerto be adapted to various gases...
Itis expected that, in the future, gas turbines will beoperated on gaseous fuels currently unutilized. The ability to predictthe range of feasible fuels, and the extent to whichexisting turbines must be modified to accommodate these fuels, restson the nature of these fuels in the combustion environment.Understanding the combustion behavior is aided by investigation of syngasesof similar composition. As part of an ongoing project atthe Lund University Departments of Thermal Power Engineering and CombustionPhysics, to investigate syngases in gas turbine combustion, the laminarflame speed of...

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