Newtonian and non-Newtonian viscous flows in nozzles

A study of laminar, Newtonian and non-Newtonian fluids in nozzles has been undertaken. A theoretical model, previously deduced for Newtonian flows in expansions, was developed for Newtonian and non-Newtonian flows in nozzles. The model is based on a two-stream approach where the momentum and kinetic energy stored in the velocity profile of the fluid is altered by an area change of one stream relative to the other. The non-Newtonian liquids investigated were shear thinning. The model was used to investigate these non-Newtonian fluids and to justify the use of simpler, more approximate equations developed for the loss and flow coefficients. The model is compared favourably with data available in the open literature.