The influence of injection velocity and relaxation time on the spreading of tracers in viscoelastic liquids agitated by submerged, recirculating jets with low reynolds numbers

作者：Bhattacharjee Pradipto K; Kennedy Stephen P; Xu Qian; Eshtiaghi Nicky; Parthasarathy Rajarathinam^*

来源：AIChE Journal, 2017, 63(7): 3132-3140.

DOI：10.1002/aic.15640

• non-Newtonian flow
• viscoelasticity
• relaxation time
• agitated vessels
• flow visualization

We provide experimental demonstration that the spread of tracer elements in a tank containing a viscoelastic liquid and agitated by a submerged jet pointing to the base of the tank can be influenced by the relaxation time of the liquid. We analyzed the temporal spreading of the boundary of a tracer-front in two dimensions using flow visualization at early stages and found that for a given fluid, the evolution of the tracer-front at various injection velocities follows a universal trajectory when considered on a normalized time scale of , where t is observation time, vN is injection velocity and is the effective diffusivity of the tracer elements in the medium. For a different fluid, at a given , the trajectory scales with the relaxation time of the fluid. The importance of relaxation time to the evolution of a tracer-front is something previously unreported.

• 出版日期2017-7