Development of mixing time correlation for a double jet mixer

Abstract

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).

RESULTS: A mixing time correlation was developed in terms of all the parameters using dimensional analysis. The constants and powers of the parameters involved in the correlation developed were estimated using a least square method to calculate the straight line that best fitted the mixing time data obtained during the experiments. The effects of change in angle of inclination of jet2 (θ₂), radial angle of jet2 with respect to jet1 (Φ₂) and diameter of jet2 (d₂) on mixing time were analyzed and compared with the experimental mixing time.

CONCLUSION: The correlation developed based on the dimensional analysis and least square method predicts the mixing time for a double jet mixing tank. Copyright © 2009 Society of Chemical Industry