聚合物流体入口自然收敛半角和涡流长度比方程的建立和初步验证

Establishment and Preliminary Validation of the Equations Involving Half Angle of the Entry Natural Convergence and Vortex Length Ratio for Polymer Fluids

入口收敛流动是聚合物流体黏弹特性的重要表现,流体入口自然收敛半角和涡流长度比是表征入口收敛流动的重要参数。对已提出的基于等效思想和最小能原理推导的在圆形流道的入口收敛流动方程进一步分析,引入黏度因子,提出了流体的入口自然收敛半角和涡流长度比的方程。结果表明,基于推导的方程对流体入口自然收敛半角和涡流长度比的预测与实验数据相符。随着Bagley校正因子的增加,流体入口自然收敛半角减小,涡流长度比增加。随着流道收缩比的增加,流体入口自然收敛半角先增大,然后几乎保持不变,而涡流长度比随着流道收缩比的增加而减小。

Entry converging flow is an important performance of the viscoelastic property for polymer fluid, the half angle of fluid entry natural convergence and the vortex length ratio are important parameters characterizing the entry converging flow. In this paper, the different equations of the entry converging flow in the circular runner published previously, which were based on equivalent thought and principle of minimum energy, were analyzed by introducing the viscosity factor. The half angle of the fluid entry natural convergence and the vortex length ratio of the entry converging flow were proposed accordingly. The result showed that predicted values of half angle of the fluid entry natural convergence and vortex length ratio based on the proposed equations accorded with the experimental values. With increasing Bagley correction factor, the half angle of the fluid entry natural convergence decreased and the vortex length ratio increased. With increasing of runner contraction ratio, the half angle of the fluid entry natural convergence initially increased but then was almost constant. Moreover, the vortex length ratio decreased with increasing runner contraction ratio.