The effects of different perforated structures on fluid mixing characteristics of rotational–perforated static mixers

Abstract Mixing operations are significant in the petrochemical industry. The rotational‐perforated static mixer (RPSM) has a flow structure in which rotational flow and perforated flow are coupled. The perforated structure in RPSM is the key to promoting mixing. It is important to understand the effect of perforated structure on mixing characteristics. In this study, the mixing characteristics of RPSM with different perforated structures were evaluated by the coefficient of variation ( CoV ) using planar laser induced fluorescence (PLIF) in the laminar flow range with different installation methods and operating conditions. We performed a significance analysis of the factors affecting the CoV to identify the key parameters for optimizing the mixing performance. The results showed that the perforated structure can enhance the mixing performance of RPSM. Compared with uniformly perforated distribution, the centrally perforated blade was conducive to fluid mixing. The mixing performance improved with the increase in Reynolds number and was less affected by mixing time. The mixing performance of backward installation was better than forward installation. The inlet Reynolds number with Rhodamine 6G and water: Re R = 1231, Re W = 246; the lighting distance of 10 cm and element number of 4; the CoV value reached a minimum of 0.013 for the blade with a central perforated diameter of 8 mm, indicating the optimal mixing performance.