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通过耦合Brown构形场的有限体积法,对基于FENE(Finite Extension Non-linear Elastic)珠-簧链分子模型的平板Couette流动进行了模拟。不但得到了流动过程中的速度、应力等宏观信息,还得到了分子链的位形、分子链的取向角以及拉伸量等微观信息。另外,还研究了弹簧的最大拉伸长度b和Weissenberg数We对聚合物稀溶液流变性质及分子构象的影响。模拟结果表明,随着b和We增大,代表弹性的第一法向应力差增大,分子链的拉伸量增大,取向角减小。但是,b和We对剪切应力的影响相反,即b增大,剪切应力增大;We增大,剪切应力则减小。
The Couette flow in a plate based on the FENE (Finite Extension Non-linear Elastic) bead-chain model was simulated by the finite volume method coupled with the Brown configuration field. It not only got the macro information such as velocity and stress in the flowing process, but also got the microscopic information such as the configuration of the molecular chain, the orientation angle of the molecular chain and the stretching quantity. In addition, the influence of the maximum spring length b and the Weissenberg number We on the rheological properties and the molecular conformation of polymer dilute solutions was also investigated. The simulation results show that as b and We increase, the first normal stress difference representing the elasticity increases, the amount of stretching of the molecular chain increases, and the orientation angle decreases. However, the influence of b and We on the shear stress is the opposite, that is, b increases and the shear stress increases. When We increases, the shear stress decreases.