不同棒束结构稠密栅元通道内的湍流CFD研究

采用URANS（UnsteadyReynoldsAveragedNavierStokes）方法对不同棒束结构稠密栅元通道（P/D=1.001～1.2）内的湍流流动进行CFD模拟。研究分析了不同Re（Re=5000~215000）的湍流流动的主流速度、壁面剪应力、湍动能等参数。研究表明：在较稠密的棒束（P/D<1.1）通道内，P/D的变化对子通道内主流速度和剪应力分布均有较大影响。本文的模拟结果也验证了在达到临界P/D前（即使δ/D<0.011），交混因子Y和δ/D成反比关系。对于固定的棒束结构（P/D=1.062），当Re达到一定值（Re=9600）时，子通道内主流速度和剪应力分布对Re的变化不敏感。

CFD Simulation on Turbulent Flow in Tight Lattice Fuel Assemblies

In this paper,URANS(Unsteady Reynolds Averaged Navier Stokes) methodology was applied to the prediction of turbulent flow inside tight lattice rod bundles with different P/D ratios,i.e.from 1.001 to 1.2.The turbulent flow with Reynolds number ranging from 5 000 to 215 000 was investigated by analysing the bulk velocity,wall shear stress and turbulent intensity distributions in the subchannel.The results show significant effect of P/D on stream wise velocity and wall shear stress in very tight lattice(P/D<1.1).The results also indicate that the mixing factor(Y) has an inverse proportion relation to δ/D,even though δ/D is smaller than 0.011.When Reynolds number reaches certain value in tight lattice,the bulk velocity and wall shear stress are less sensitive to Reynolds number.