No abstract

Mixing is one of the common unit operations employed in chemical industries. It is used for blending of liquids, flocculation, homogenization of mixtures, ensuring proper heat and mass transfer in various operations, prevention of deposition of solid particles, etc. Earlier research aspects were focused on experimental estimation of mixing time and proposing suitable correlations for the prediction of mixing time, the recent one being on flow visualization. However, most of the results reported in the literature deal with liquid flow with multi jets, whereas the effect of radial angle on mixing time was not studied. This study describes the effect of radial angle on mixing time as determined by experiment and simulation. A computational fluid dynamics (CFD) modeling is done for a jet mixing tank having two jets for a water–water system. Nozzle configuration for jet1 was fixed on the basis of our earlier studies (2/3rd position, flow rate 9l/m, nozzle angle 45° and nozzle diameter 10 mm). Mixing times were estimated for different jet2 configurations (jet angle 30°, 45° and 60°; radial angles 60°, 120°, 180°) located at different tank heights (2/3rd and 1/3rd from the bottom of the tank). The results obtained for mixing time for jet mixing in a tank with two jets are analyzed and the suitable nozzle angle, radial angle and position are proposed for the jet2 of the jet mixer considered in the present study. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.

BACKGROUND: Jet mixing is one of the simplest methods to achieve mixing. There have been a number of experimental studies concerned with jet mixing; some of these studies report empirical correlations. The existing correlations are not useful where there are significant deviations from the idealized conditions. Most correlations reported in the literature deal with liquid flow with single or multiple jets, whereas the effect of radial angle on mixing time was not studied. This present study investigates the effect of operating parameters on experimental mixing time in a double jet mixer. Nozzle configuration for jet1 was fixed based on earlier studies (2/3rd position, nozzle angle 45• and nozzle diameter 10 mm). Mixing times were estimated for different jet2 configurations of jet angle (30• , 45• and 60 • ), radial angles (60 • , 120• , 180 • ), jet diameter (5 mm and 3 mm) and located at different tank heights (2/3rd and 1/3rd from the bottom of the tank).