Quantitative visualization of the mixing characteristics of a multilayer static mixer by planar laser-induced fluorescence

Abstract

Mixing is an inseparable part of many industries. Static mixers are motionless inserts that are widely used for mixing. In this study, planar laser-induced fluorescence (PLIF) was used to study the mixing characteristics of a multilayer static mixer. The effects of the arrangement angle of layer elements of the static mixer were examined. Arrangement angles of 0°, 45°, and 90° were investigated at four different flow-rate ratios of two mixing fluids. The mixing performance of each angle was evaluated with both qualitative and quantitative approaches. The volume fractions of the flows were obtained from the PLIF results, and the mixing index was calculated. The friction factor was measured to assess the pressure loss of each arrangement angle. The results show that the arrangement angles do not affect the mixing index for higher flow ratios. However, at the lowest flow ratio, the angle of 45° resulted in the highest mixing index of 74.9%, while at 0° and 90°, the values reached 66.4% and 69.8%, respectively. In regard to pressure loss, 45° also resulted in the lowest friction factor.