SINOPSIS

In our LES, an improved immersed boundary method and a new one-equation dynamic SGS model was applied for accurate simulation of complicated wall boundary of industrial interest. Our computational results reasonably reproduced previous data obtained by experiments and computations. The results were able to represent the effect of flow geometry: the flow around the mixing-vane causes the swirl and the large-scale fluctuation enhancing heat transfer; turbulence stress promotes the decay of the swirl more strongly than in a pipe; but it produces a vortex in rod gap enhancing enthalpy mixing between channels. These results suggested that LES technique become a useful tool for designing the spacer grid by predicting the effect of flow control.