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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...
The objective of this work is to establish the design principles of a proton exchange membrane (PEM) fuel cell (FC) stack for portable applications. A combination of experiments and numerical simulations were carried out and the results analyzed to enhance understanding of the behavior of this portable PEMFC stack. A three-dimensional (3D) computational fluid dynamics (CFD)-based methodology was used to predict such as the current and temperature distributions of this portable PEMFC stack. The results show how the baseline operation and original design of this stack impact the local...
The paper presents a combined experimental and numerical program directed at improving the accuracy of conjugate heat transfer CFD simulations of engine water cooling jackets. As a first step in the process, a comparison between experimental measurements from a test facility at Villanova University and CFD numerical predictions by at the University of Modena is reported. The experimental test section consists of a horizontal aluminium channel heated electrically and supplied with a constant volumetric flow rate. The operating fluid is a binary 50/50 mixture by volume of ethylene-glycol and...
The conventional advection-dispersion equation cannot adequately describe all processes driving solute transport in heterogeneous systems. This dissertation focuses on the individual influences of both chemical (Chapter 2) and physical processes (Chapters 3 and 4) which affect solute transport. In Chapter 2 we analyzed uranium transport in natural sediment using the chemical multirate mass transfer model available within the STAMMT-L software. This model was used due to many uncertainties of the overall mass transfer influences, which were generalized into a distribution of first-order rate...

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