The effect of the hydrodynamic interaction on the rheological properties of Hookean dumbbell suspensions in steady state shear flow

The diffusion equation for the configurational distribution function of Hookean dumbbell suspensions with the hydrodynamic interaction (HI) was solved, in terms of Galerkin’s method, in steady state shear flow; and viscosity,first and second normal-stress coefficients and molecular stretching were then calculated. The results indicate that the HI included in a microscopic model of molecules gives rise to a significant effect on the macroscopic properties of Hookean dumbbell suspensions. For example, the viscosity and the first normal stress coefficient, decreasing as shear rate increases, are no longer constant; the second normal-stress coefficient, being negative with small absolute value and shear-rate dependent, is no longer zero; and an additional stretching of dumbbells is yielded by the HI. The viscosity function and the first normal-stress coefficient calculated from this method are in agreement with those predicted from the self-consistent average method qualitatively, while the negative second normal-stress coefficient from the former seems to be more reasonable than the positive one from the latter.     

定常流中聚合物分子的取向

本文将求解纳维-司托克斯方程的有限元方法与分子模型(多球刚杆模型)相结合,从而恰当地模拟刚棒状聚合物分子稀溶液的流动。对于几种定常流动问题,求解了流场和多球刚杆模型的最可几取向,并用图显示了这些结果。这些结果说明了这种方法处理的合理性。     

聚合物分子模型的Brown动力学模拟

介绍了研究聚合物分子模拟流变性质的Brown动力学模拟方法,综述了有关这方面的研究工作．在通常情况下,将分子模型的数值模拟与求解流动守恒方程的数值解法相结合,便有可能用分子模型去代替连续介质力学的本构方程,来模拟聚合物流体的复杂流动．本文介绍了这一方法的产生背景、最新进展以及优点．      

流化床气泡的统计测量原理

鼓泡现象是气-固流化床的特征,床内气泡相的流动分布对反应器性能有重大影响。由于床内气、固两相流动的复杂性,至今不但在理论上难以确切描述,而且对鼓泡现象本身也还有待于进一步认识,因此寻求一种有效的测量方法有极为重要的意义。十多年来,不少科学工作者致力于流化床内气泡运动的实验研究,所用的测量方法有几种。一种是用电影摄影机拍摄流化床表面影片,根据气泡喷发时的直