CFD Based Nozzle Design for a Multijet Mixer

• Published in: Chemical engineering and processing 2020-11, Vol.157, p.108121, Article 108121
• Main Authors: Gyurik, L., Ulbert, Zs, Molnár, B., Varga, T., Chován, T., Egedy, A.
• Format: Article
• Language: English
• Subjects: CFD modelling; mixing efficiency; nozzle design; particle tracking; Poincaré map
• ISSN: 0255-2701; 1873-3204
• DOI: 10.1016/j.cep.2020.108121

[Display omitted] •Validated CFD model is proposed to simulate the behavior of a multijet mixer.•Particle tracking study and Poincaré maps are used for data processing.•A method to characterize the mixing efficiency of multijet nozzles is suggested.•The best choice of nozzle construction is determined based on the fluid mixedness. In this work, the mixing efficiency is studied in case of different multibore nozzle constructions in a pretreatment part of a continuous reactor. Computational Fluid Dynamics (CFD) is used to model the multijet mixer, and design of the nozzle is carried out by simulation studies. The simulation model is validated by residence time experiments performed in a laboratory device with the same spatial scale as in the industrial case. The aim of the study is to find the most effective nozzle design out of some limited number of physically realizable constructions considering predefined mixing metrics. Poincaré maps are prepared by a particle tracking study, and the derived mixing maps are introduced to give a first impression about the quality of mixing. According to the quantified results, the nozzle with 6 bores angled at 23 degrees is proposed as the optimal construction, which reduces the volume of the dead zones and increases the mixing efficiency, providing a proper pretreatment of the inlet stream for the consequent reactor unit.