Bubbles dynamics and boiling of polymeric solutions

Luikov Heat and Mass Transfer Institute, Belarus 

Solutions of polymers exhibit a number of unusual effects in flows. Complex mechanical behavior of such liquids is governed by qualitatively different response of the medium to applied forces than low-molecular fluids. In hydrodynamics of polymers this response is described by rheological equation that relates the stress tensor, a, to the velocity field. The latter is described by the rate-of-strain tensor, e 

For incompressible fluid V v = 0, e = s and rheological equation can be formulated in the form of the x- dependence from e. Compressibility of the liquid must be accounted for in fast dynamic processes such as acoustic waves propagation, etc. For compressible medium the dependence of pressure, p, on the density, p, and the temperature, T, should be specified by equation, p = p, T), that is usually called the equation of state. 

The simplest rheological equation corresponds to incompressible viscous Newtonian liquid and has the form 

Generalizations of the Newton s flow law [7.2.3] for polymeric liquids are aimed to describe in more or less details the features of their rheological behavior. The most important among these features is the ability to accumulate elastic deformation during flow and thus to exhibit the memory effects. At first we restrict ourselves to the case of small deformation rates to discuss the basic principles of the general linear theory of viscoelasticity 

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