直管中黏弹性流体二次流的非线性特性分析  

Nonlinear Analysis of Secondary Flow of Viscoelastic Fluid in Straight Pipe

作　　者：花少震 段翠芳 刘华博 孟凡净 王强胜 孔春辉 HUA Shaozhen;DUAN Cuifang;LIU Huabo;MENG Fanjing;WANG Qiangsheng;KONG Chunhui(School of Mechanical Engineering,Henan Institute of Technology,Xinxiang 453003,China)

机构地区：[1]河南工学院机械工程学院,河南新乡453003

出　　处：《河南工学院学报》2021年第1期22-27,共6页Journal of Henan Institute of Technology

基　　金：河南省高等学校重点科研项目(21A110007,21A130001,21B480002,19B470002);河南省科技攻关项目(212102210432);河南省高等学校青年骨干教师培养计划(2019GGJS265);河南工学院博士科研启动费资助(KQ1587)。

摘　　要：用Giesekus本构方程表征黏弹性流体的流变行为。采用数值模拟方法,发展了基于有限体积法的黏弹性数值算法,并用经典4∶1收缩流基准问题验证了所发展算法的有效性。然后分别模拟了内切圆直径等于20mm时横截面为正3-8边形以及椭圆的长直管道的黏弹性流体的流动,结果发现二次流产生涡的个数是边个数的二倍,椭圆横截面上二次流产生四个涡,直管中黏弹性流体二次流中涡的产生条件是横截面为变曲率边界。通过比较不同非线性系数发现,当非线性系数为0时直方管二次流为中心点流出的源流,且其二次流速度远小于非线性系数等于0.18时的二次流速度。结果表明,文中所发展算法能有效模拟黏弹性流体在直管中的二次流现象,而且数值结果所呈现的二次流非线性特性和理论上的非线性特性吻合较好。In order to analyze the nonlinear characteristics of the secondary flow of viscoelastic fluid in straight pipe,the rheological behavior of viscoelastic fluid was characterized by Giesekus constitutive equation.A viscoelastic numerical algorithm based on finite volume method was developed.The effectiveness of the algorithm was verified by the classical 4:1 contraction flow benchmark problem.Then,flow of viscoelastic fluid in long straight pipes,whose cross-section are equilateral polygons with 3 to 8 boundaries and with a inscribed circle’s diameter equaling to 20 mm,are simulated respectively.Viscoelastic flow in long straight pipe with ellipse cross-section is also simulated.The results show that the number of vortexes in secondary flow is twice of the number of boundaries.The secondary flow produces four vortices on the elliptic section,and generation of vortices in the secondary flow of viscoelastic fluid in straight pipe is that the cross-section has variable curvature boundaries.By comparing different nonlinear coefficients,it is found that the secondary flow of the rectangular pipe is the source flow from the center point atα=0,and velocity of the secondary flow is much smaller than main flow when the nonlinear term coefficient is equal to 0.18.The results show that the developed algorithm can effectively simulate the secondary flow of viscoelastic fluid in a straight pipe,and the nonlinear characteristics of the secondary flow presented by the numerical results are in good agreement with the theoretical results.

关 键 词：Giesekus 黏弹性 非线性 二次流 

分 类 号：O376[理学—流体力学]