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The diameter effect on the heat transfer of supercritical water (SCW) flows in horizontal round tubes has been studied using computational fluid dynamics (CFD) technique. The numerical simulations are carried out by the STAR-CD solver combined with the user developed subroutines that control the numerical calculation procedures. Through the tests it is found that the discretization scheme using CD, LUD or MARS will not affect the accuracy of the numerical simulations. Through the diameter effect studies, it is found that the heat transfer of supercritical water flows in the horizontal round...
The present paper deals with noise produced by an orifice placed in a circular duct. Such noise is mainly generated by the orifice itself and by the unsteady flow and turbulence in the orifice wake. The main objective of the present work is to develop a numerical prediction tool for the acoustic energy level produced by the orifice placed in a ducted flow. The model is based on the solution of the Navier-Stokes equations, for the compressible turbulent flow, inside the duct and in the near-region outside the duct termination, and on the Ffowcs Williams-Hawkings surface method for the...
During protected loss of flow (PLOF) accidents in fast breeder reactors the temperature at the core outlet experiences variation depending on the pump coastdown. In case of long flow coastdown the temperature at the core outlet will decrease and sodium stratification will occur in the upper plenum due to the effect of gravity. The geometrical characteristics of nuclear reactor such as Monju (presence of shrouds with circumferential holes), can moreover create currents with different temperature which move towards the hot-leg piping system. As a result uneven temperature distribution is likely...
Numerical and experimental investigations of wall jets with tabs are performed. The tabs were rectangular thin metal plates placed at the jet outlet, either at the top mid boundary, or at the mid-sections of the three unbounded boundaries, perturbing into the jet. The numerical analyses and experimen ts were carried out ata maximum mean velocity of 15 m/sec. which corresponds to an approximate jet Reynolds number based on the vertical jet dimension of 13027. The numerical analyses were performed with the STAR-CCM+ commercial software wi th the Wilcox K-ω tur bule nce model. The e xperi mental...
The complete engine process (inlet stroke, direct methane injection, compression, combustion and exhaust stroke) in a direct injection methane engine is investigated using the Reynolds Averaged Navier Stokes (RANS) and the Large Eddy Simulation (LES) approaches offered by Star-CD. Single-cycle RANS and LES simulations based on k − ǫ and k − l turbulence models, were performed first to assess the potential improvement offered by LES. The model approaches of RANS and LES in the fields of wall heat losses and combustion are compared and the differences are discussed. Especially in the combustion...
The paper presents a numerical activity directed at the analysis and optimization of internal combustion engine water cooling jackets, with particular emphasis on the fatigue-strength assessment and improvement. In the paper, full 3D-CFD and FEM analyses of conjugate heat transfer and load cycle under actual engine operation of a single bank of a current production V6 turbocharged Diesel engine are reported. A highly detailed model of the engine, made up of both the coolant galleries and the surrounding metal components, i.e. the engine head, the engine block, the gasket, the valve guides and...
A multidimensional computational fluid dynamics (CFD) simulation of a constructed syngas chemical kinetic mechanism was performed to evaluate the combustion of syngas in a supercharged dual-fuel engine for various syngas initial compositions under lean conditions. The modelled results were validated by comparing predictions against corresponding experimental data for a supercharged dual-fuel engine. The predicted and measured in-cylinder pressure, temperature, and rate of heat release (ROHR) data were in good agreement. The effect of the hydrogen peroxide chain-propagation reaction on the...

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