【摘要】 弯管广泛地存在于工业应用的多个领域中,为研究弯管内速度场和压力场的分布,采用CFD技术对不同流态下圆形截面90°弯管内的二次流(迪恩涡)进行了数值模拟。模拟过程采用有限体积法进行空间离散,并利用带旋流修正的k-ε模型进行计算。模拟结果表明:层流状态下沿流动方向截面上的峰值速度和峰值全压变化较小,涡核位于半截面中心;当流体处于过渡区时,流动方向截面上的峰值全压呈递减趋势,峰值速度在0～60°截面上递减,在90°截面上突增,并且涡核开始出现"外扩";完全湍流区时,流动方向截面上的峰值全压显著递减,涡核位置明显"外扩"。更多还原

【Abstract】 In order to study the velocity field and pressure field of the secondary flow(Dean Vortices)in curved tubes,numerical simulation was carried out in different flow patterns with the help of CFD software.The finite Volume Method was employed during the spatial discretization and the calculation was carried out in terms of the Realizable k-εturbulence model.Simulation results showed that the maximum velocity and maximum total pressure in the cross-section along the flow direction kept almost unchanged when the flow was in laminar region(v=0.04m/s),and the cores of the vortices were found right in the center of the semi-circular;when the flow was in transition region(v=0.25m/s),the maximum total pressure and velocity in the cross-sections along the flow direction decreased gradually while the maximum velocity increased suddenly in the 90°cross-section,with the cores of the vortices beginning to move outward;However,when the flow developed to turbulence flow(v= 0.5m/s),the maximum total pressure decreased apparently and the cores of the vortices significantly moved outward.更多还原