Turbulent Characteristics and Design of Transverse Jet Mixers with Multiple Orifices

Abstract

We investigated and compared the turbulent characteristics of two-liquid mixing in single-orifice and multiorifice-impinging transverse (MOIT) jet mixers through large eddy simulations and the planar laser-induced fluorescence technique. Our focus is on evaluating the roles played by the interactions among the jets in the mixing intensification. The turbulent vortex structures, time-averaged mean concentration distributions, root-mean-square of the concentration fluctuations, probability density function, and power spectral density are discussed. For the MOIT jet mixer with large jet-to-crossflow velocity ratios, direct impingement of the jets enhances the mixing by speeding up the evolution of the counter-rotating vortex pairs, resulting in reduction in the vortex scale, increasing the vortex magnitude, and homogenizing the vortex distribution. The effect of the mixer scale-up on the turbulent characteristics was also studied. Moreover, we selected a specific MOIT jet mixer to perform optimization of the orifice number and diameter of the jet flow with fixed other parameters.

Liquid mixing intensification by adding swirling flow in the transverse jet mixer

“…Firstly, numerical prediction accuracy is evaluated. As the grid sensitivity analysis has been carried out in our previous work, 26 here we only validate the simulation results from the wall y + value discussion, power spectral density (PSD) analysis, and time‐averaged concentration distribution comparison.…”

“…The SIMPLE algorithm is adopted for pressure–velocity coupling, and the bounded central differencing method is used for the spatial discretization of the momentum, turbulent kinetic energy, and concentration. Time step is set to 0.0002 s. The mesh generation method, boundary condition setting, and grid sensitivity analysis has been discussed in our previous work 26 and is also adopted in this work.…”

“…The multiorifice‐impinging transverse (MOIT) jet mixer, in which the jet flow is injected into crossflow through multiple orifices, can accomplish fast liquid mixing in few to tens of milliseconds in our previous studies 26,27 . The objective of this work is to carry out further investigation on the mixing intensification when the swirling flow is added into the jet flow or the crossflow.…”

CFD–PBE Model and Simulation of Continuous Antisolvent Crystallization in an Impinging Jet Crystallizer with a Multiorifice at Different Positions

“…Effect of the Velocity Ratio on Mixing and the Crystallizer. Luo et al 9 have found in their study that the ratio of jet and cross flow velocity (r) is the main factor affecting the mixing. Although water was used as the working medium in the study, they did not consider the density and viscosity differences between particles, the solvent, and the antisolvent.…”

“…Therefore, secondary nucleation caused by impellers would lead to broad CSD and a small crystal size. Compared with tank crystallizers, tubular crystallizers (such as impingement jets ,,, and coaxial nozzle crystallizers) do not have such mechanical collisions. Due to uniform supersaturation and residence time distribution, it can produce crystals with a narrower CSD.…”