Reynolds-Averaged and Large-Eddy-Simulation Studies of Turbulent Mixing in a Square Channel
The qualification of turbulent mixing processes is of fundamental importance in many engineering applications, including nuclear reactor thermal-hydraulics operation and safety. It is considered numerically challenging to represent turbulent mixing specially for high Reynolds number flows, since mixing process takes place over a wide range of turbulent scales. It is therefore essential to develop a detailed understanding of the relevant phenomena, and to validate those accepted numerical models in current use in design and optimization of nuclear reactors. In this work, a comparative study of turbulent mixing is reported for the setup of an experiment consisting of a square channel in which two co-current water streams, with different electrical conductivities, and with relatively high Reynolds numbers, are allowed to flow over a splitter plate to developing and then get mixed together. Different turbulence modeling strategies to predict scalar mixing are compared; namely the standard k-e turbulent model, the Reynolds Stress transport Model (RSM) and Large Eddy Simulations (LES). In addition, the ability of two Subgrid Grid Scale (SGS) models (the classical Smagorinsky-Lilly model and the Germano’s dynamic model) to predict the mixing process is assessed. The LES simulations showed better overall quantitative comparisons for the mixing scalar. The analysis is rounded-up with an assessment of the Bounded-Central Difference (BCD) scheme used for discretisation of the advection terms in LES equations.
Turbulent mixing LES SGS models RANS models passive scalar transport
M. Sharabi B. Ni(c）eno
Paul Scherrer Institute 5232 Villigen PSI, Switzerland
国际会议
上海
英文
583-594
2010-10-10（万方平台首次上网日期，不代表论文的发表时间）