Etude numérique du transfert de masse d'un écoulement de Taylor-Couette-Poiseuille

Abstract

The influence of the radius ratio N and the number of Schmidt on the mass transfer is numerically investigated in the gap between two concentric cylinders with an imposed axial flow. The annular space varies from 0.3 to 0.75. The Reynolds and Schmidt number vary respectively from 100 to 2500 and from 0.7 to 1000. Two cases are considered; inner or outer cylinder is activated. The results show that hydrodynamic instabilities appear for values of Sc Re= 10+4. The radial concentration profile shows the existence of an important gradient at the activated wall that it varies with the axial position. The variation of the mass transfer coefficient K for different Schmidt number and a fixed radius ratio show the increase of the mass transfer with the Schmidt number. The reduction of the annular space promotes mass transfer. The radial concentration gradient is more important for gases (small values of Schmidt) then for liquids (large values of Schmidt). The mass transfer is more important at the inner cylinder. The Sherwood number is proportional to Re+0..3.