泡沫流体的剪应力与法向应力差

本文在同时考虑表面张力与粘性力的情况下,以三维模型—长菱形十二面体及泡沫的应力张量表达式为基础,得出了泡沫的剪应力及法向应力差表达式,并通过计算机进行了求解,讨论了泡沫粘度、泡沫大小等因素对剪应力及法向应力差的影响。 实验使用了 RMS-605 大型流交仪、RV-2 流变仪及毛细管流变仪测定泡沫流变特性。消除了表面滑移影响后得到的剪应力与法向应力表数据与理论结果较接近,说明理论模型具有一定的实用价值。

STUDY ON THE SHEAR STRESS AND NORMAL STRESS DIFFERENCE OF FOAMS

A theoretical stress tensor model that includes surface tension forces and viscous forces is developed by considering the three-dimensional spatially periodic cells of dodecahedron. Meanwhile, the shear stress and normal stress difference under various shear rates are calculated by computer.The rheological properties of foam have been measured by RMS-605 Rheameter, Rotary Viscositymeter-2 (Rv-2) and Capillary Rheometer. The theoretical results are close to the experimental data when the effect of slip at viscometer wall is eliminated. This means that three-dimensional foam model is quite close to real foam and is of value in practice.