DYNAMICAL BEHAVIOR OF DRAG-REDUCING POLYMER-SOLUTIONS

Related to the problem of the drag-reduction mechanism due to the elastic properties of macromolecular additives, we study theoretically and experimentally the dynamically behaviour of the molecules and the corresponding flow field. Optical properties, orientation, configuration or change of shape are studied by flow birefringence in classical or original, elongational flow devices. The dependence of the birefringence threshold on the molecular weight, nature, ionic character, concentration and level of degradation of the polymer is studied. The flow field is determined experimentally and by computation using a simple rheological model. A correlation with drag-reduction measurement in capillaries is tried. © 1979.