旋转矩形截面弯管内流动特性的研究

Research on the characteristics of the fluid flow in rotating curved rectangular duct

本文利用数值计算方法研究了三种旋转矩形截面 ( η =1,η >1,η <1)弯管内的粘性流动 ,分析了在离心力和科氏力共同作用下二次流动、轴向主流、摩擦系数比随各参数的变化情况 ,所得的结果与已有文献的结果 (数值结果和实验结果 )非常吻合。计算结果表明 :对于宽高比 η 1的矩形截面 ,截面上最多可以存在 8个涡 ;若 η >1,截面上最多可以出现 6个涡 ;摩擦系数比和二次流函数最大值在F≈ - 1时取得最小值 ;计算结果还表明 ,η对高速旋转弯管内的摩擦系数比的影响程度要明显高于对静止的弯管内的摩擦系数比的影响程度 ,最后本文给出 η

An incompressible viscous steady flow through a rotating curved rectangular duct is studied numerically employing the control volume integral method. The combine effects of the Coriolis force (due to rotation) and the centrifugal force (due to curvature) on the flow structure and the fraction factor ratio are examined in detail for three type rectangular duct: η>1,η=1,η<1 , where η is the aspect ratio. The structures of the flow are studied during the range -2.0F1.0 , where F represents the ratio of the Coriolis force to the centrifugal force, De =400 and 100 for η=1 , only De =400 for η ≠1. In this range, The complicated secondary flow vortices are obtained. For η 1, the most number of the secondary cell is eight and for η>1 , this number is six. The maximum of axial velocity is pushed either outside or inside, which depends on the value of F . The fraction factor ratio reaches its minimum value that is almost 1 at F ≈-1 and the effects of η on the fraction factor ratio depend on R o . It is also shown when R o is small, the fraction factor ratio decreases rapidly against R o and the contours of axial velocity are almost uniform along the y axis and has a shape like dumbbell.