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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...
The commercial CFD software STAR-CCM+ was used to simulate transportation of viscous oil in a horizontal pipe. The CFD model was first validated against analytical solution for wall shear stress in laminar flows with constant physical properties. The model was then used to investigate the effects of heat loss since the pipe is subjected to cooling by the sea water on the sea bed. The results show strong thermal stratification across the pipe with cooler fluid at the bottom of the pipe and warmer fluid near the gas-liquid interface. A layer of cooler fluid is also found next to the pipe wall...
This paper presents a novel turbocharging system applied to four-stroke diesel engines, which is named modular multi-purpose pulse converter (MMPC) turbocharging system. Two-dimensional steady flow simulations of the MMPC turbocharging system are performed with STAR-CD code. A one-dimensional unsteady flow simulation code finite volume method and total variation diminishing (FVM–TVD) has been developed. Using FVM–TVD, flow predictions in the diesel engine 8L250Z are carried out in the unsteady state with the mixed pulse converter (MIXPC) turbocharging system and MMPC, respectively. It is...

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