Some Experimental Results on Laser Doppler Velocimetry (LDV) and Birefringence (FIB) Studies of Non-Newtonian Fluids Flow Through Rectangular Channels

In the present study, the turbulence behaviour of polymer solutions is investigated using laser-Doppler velocimetry (LDV). At the same time, an attempt is made to determine a possibly occurring extension and orientation of the macromolecules by flow-induced birefringence (FIB). Flow-dynamic and rheo-optical experiments are presented which were performed in a smooth square channel in the area of the fully developed turbulent flow. The turbulent flow properties of aqueous solutions of PAAM and Xanthan Gum were studied. The Reynolds number was 30000. The concentration of the polymer solutions was varied between 300 wppm and 800 wppm for PR2300 and between 30 wppm and 120 wppm in the case of Xanthan Gum. The obtained experimental data indicate a significant dependence of the turbulent flow properties on the molecular structure of the polymers used. Furthermore, the extension and orientation of the macromolecules on the turbulent flow properties was investigated.