Mixing times in single andmulti-orifice-impinging transverse (MOIT) jet mixers with crossflow

doi:10.1016/j.cjche.2016.01.018

Abstract

Abstract: We study the macromixing behavior of single and multi-orifice-impinging transverse (MOIT) jet mixers with crossflow, in particular, the overall mixing time and the back-splash mixing time of the injected flow with the crossflow, using the PLIF technique. It is found that for a given mixer configuration, there is a critical jet-tocrossflow velocity ratio r_c at which the back-splash begins to occur. Further increase in the velocity ratio r leads to sharp increase in the back-splash mixing time, which can offset the intensification of the downstream mixing. The dimensionless overall mixing time decreases as r increases to reach either a plateau or a local minimum, and the corresponding r value represents the optimal velocity ratio r_opt for the macromixing. The momentumratio of the two liquid streams is a key factor determining r_c and r_opt. For a larger scale mixer, a higher momentum ratio is required to achieve the optimal macromixing with the minimum dimensionless overall mixing time.

Key words: Mixing, Chemical reactors, Mixing time, Jet mixer, Planar laser induced fluorescence (PLIF)

摘要： We study the macromixing behavior of single and multi-orifice-impinging transverse (MOIT) jet mixers with crossflow, in particular, the overall mixing time and the back-splash mixing time of the injected flow with the crossflow, using the PLIF technique. It is found that for a given mixer configuration, there is a critical jet-tocrossflow velocity ratio r_c at which the back-splash begins to occur. Further increase in the velocity ratio r leads to sharp increase in the back-splash mixing time, which can offset the intensification of the downstream mixing. The dimensionless overall mixing time decreases as r increases to reach either a plateau or a local minimum, and the corresponding r value represents the optimal velocity ratio r_opt for the macromixing. The momentumratio of the two liquid streams is a key factor determining r_c and r_opt. For a larger scale mixer, a higher momentum ratio is required to achieve the optimal macromixing with the minimum dimensionless overall mixing time.

关键词: Mixing, Chemical reactors, Mixing time, Jet mixer, Planar laser induced fluorescence (PLIF)

Peicheng Luo, Yuncui Tai, Yi Fang, Hua Wu. Mixing times in single andmulti-orifice-impinging transverse (MOIT) jet mixers with crossflow[J]. , 2016, 24(7): 825-831.

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