Experimental and numerical investigation on mixing and axial dispersion in Taylor-Couette flow patterns

Marouan Nemri (1, 2) , Éric Climent (1) , Sophie Charton (2) , Jean-Yves Lanoe (2) , Denis Ode (2)

1 IMFT - Institut de mécanique des fluides de Toulouse
2 CEA-DES (ex-DEN) - CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire)

Taylor-Couette flows between two concentric cylinders have great potential applications in chemical engineering. They are particularly convenient for two-phase small scale devices enabling solvent extraction operations. An experimental device was designed with this idea in mind. It consists of two concentric cylinders with the inner one rotating and the outer one fixed. Moreover, a pressure driven axial flow can be superimposed. Taylor-Couette flow is known to evolve towards turbulence through a sequence of successive hydrodynamic instabilities. Mixing characterized by an axial dispersion coefficient is extremely sensitive to these flow bifurcations, which may lead to flawed modelling of the coupling between flow and mass transfer. This particular point has been studied using experimental and numerical approaches. Direct numerical simulations (DNS) of the flow have been carried out. The effective diffusion coefficient was estimated using particles tracking in the different Taylor-Couette regimes. Simulation results have been compared with literature data and also with our own experimental results. The experimental study first consists in visualizing the vortices with a small amount of particles (Kalliroscope) added to the fluid. Tracer residence time distribution (RTD) is used to determine dispersion coefficients. Both numerical and experimental results show a significant effect of the flow structure on the axial dispersion.

Mots clés: Taylor-Couette flow; Axial dispersion; Direct numerical simulation; Experiments

Domaines: Génie chimique; Mécanique des fluides [physics.class-ph]; Mécanique des fluides [physics.class-ph]

Marouan Nemri, Éric Climent, Sophie Charton, Jean-Yves Lanoe, Denis Ode. Experimental and numerical investigation on mixing and axial dispersion in Taylor-Couette flow patterns. Chemical Engineering Research and Design, 2012, ⟨10.1016/j.cherd.2012.11.010⟩. ⟨hal-00918887⟩