ENERGY DISSIPATION DISTRIBUTION AND MIXING IN A TORUS REACTOR

Abstract

Previous works devoted to the development of the swirl flow generated by rotation of the marine screw impeller in the loop toroidal reactor show that the flow structure is characterized by the existence of a secondary flow. The deformation of the axial velocity profile, due to the bends curvature and the rotation of the agitator, modify considerably the friction and the transfer near the wall. The objective of this work is to study the toroidal flow and to characterize the wall turbulence. The wall shear stress distribution in the torus were performed by using an electrochemical method. The measurements of the wall shear stress were carried out in the inner and outer walls. The evolution of the wall velocity gradient with the longitudinal distance depends on the location in the torus. These results allow to obtain information about the friction factor, which is compared with the one measured directly by using piezometric connections. The experimental determination of the axial dispersion coefficient is obtained by using the dispersion plug flow model with a total recirculation. Finally, a relationship between the turbulent characteristics and the mixing parameters has been established.

Keywords:

• Electrochemical method
• Energy dissipation
• Mixing
• Pressure drop
• Torus reactor
• Wall shear stress

Additional information

Notes on contributors

J. LEGRAND

Corresponding author. Tel.: [phone], Fax: [phone], e-mail: [email protected]