(6ey) Experimental and Numerical Studies on the Micromixing Process in Novel Reactors with Multiphase System

As a PhD candidate, my goal is to become a professor who devotes himself to research and education purpose in related chemical engineering fields. My current research including: novel reactor based on high gravity technology such as rotating packed bed (RPB) and rotor-stator reactor (RSR), numerical simulation of multiphase system and reactive flow, micromixing process and turbulence model.

Rotating Packed Bed (RPB) is an apparatus consisting mainly of a packed rotator and a fixed casing. The basic principle of RPB is to create a high-gravity environment via the action of centrifugal force as so called ‘‘Higee’’. The fluids going through the packing of RPB are spread or split into very fine droplets, ligaments, and thin films by the strong shear, resulting in a significant intensification of micromixing and mass transfer between the fluid elements. The rate of mass transfer between gas and liquid in RPB is 1–3 orders of magnitude larger than that in a conventional packed bed, allowing a dramatic reduction of reaction time. Since RPB was invented, it has been successfully applied in polymerization, absorption, distillation and preparation of nanomaterials due to its high mass transfer and micromixing efficiency. Rotor-stator reactor (RSR) is also a novel Higee device which is evolved from the RPB but employs an internal of rotor-rings and stator-rings in lieu of the packing in an RPB. Due to the unique structure, RSR can not only significantly intensify micromixing and mass transfer like RPB, but also exhibits advantages over RPB, such as better liquid distribution, less fouling, no gas cut-short, and so on. RSRs have been widely studied for their performance in the intensification of mass transfer and micromixing as well as for the preparation of ultrafine particles and emulsion.

In addition, studying the micromixing controlled process is also the main content in my PhD projects. Micromixing performance of reactors is the controlling factor for fast reactions in polymerization, pharmaceutical and crystallization applications. In recently years, combined with computational fluid dynamics (CFD), the micromixing process in reactors could be investigated comprehensively. Due to the conflict between the scale of the micromixing and the grid size of Finite Difference Method (FDM), it’s difficult to building a proper micromixing algorithm. Therefore, numerical simulation of practical applications related to micromixing processes is still challenging.

CFD technique has been widely used in academic researches and industrial applications when it comes to fluid flow. Turbulence modeling as a fundamental part of CFD has great effect on the flow characteristic and mass transfer process in numerical simulation. Due to the computational cost and grid requirement of Direct Numerical Simulation (DNS) and Large Eddy Simulation (LES), many one- and two-equation turbulence models have been developed based on Reynolds-Averaged Navier-Stokes (RANS) and Boussinesq approximation. However, certain deficiencies in the validation accuracy of the models still exist, especially in complex flow conditions, such as strong rotation and multiphase flow (typical flow characteristic in RPB). Proper turbulence model is needed to increase the accuracy of flow simulations for mildly separated flows, flows with rotation and curvature effects, and flows with surface roughness.

Current PhD Dissertation:

“Experimental and numerical studies on the micromixing process in novel reactors with viscous fluids”

Research Experience:

Under the supervision of Prof. Chen Jian-Feng (Academician of Chinese Academy of Engineering, Beijing University of Chemical Technology), studying the micromixing controlled process, practical applications such as polymerization and alkylation process in RPB and microreactors, experimentally and numerically.

Under the supervision of Prof. Ramesh K. Agarwal (William Palm Professor of Engineering, Washington University in St. Louis), I finished a Joint doctoral program. I studied a new turbulence model-Wray-Agarwal model, including rotation/curvature and surface roughness corrections, and implemented it

Teaching Interests:

As mentioned above, my goal is to become a professor for research and education purpose in related chemical engineering fields. I was a teaching assistant in the courses of “Chemical Engineering Principles”, “Transport phenomena” and “Chemical Reaction Engineering”. Besides, based on the my research background of chemical engineering and CFD, I became proficient in numerical calculation of multiphase flow, reactive flow and high performance computing.

Future Direction:

As mentioned in “Reaction engineering: Status and future challenges (Dudukovic M P. Chemical Engineering Science, 2010, 65(1): 3-11.)”, reactor miniaturization provides opportunities for scale-up in parallel, and quantification of multiphase flow fields reduces the risk of scale-up. Novel reactor plays a significant role in process intensification. My future direction will focus on the design and optimization of Higee reactors and microreactors in multiphase system using multiscale method and visualizaiton technology, including Finite Difference Method, Lattice Boltzmann Method or even Molecular Simulation combined with validation experiments.

Besides, with the rapid development of numerical method, new models and algorithms are needed (such as mass transfer model and turbulence model) for complex flow simulation in order to obtain better accuracy and computational efficiency, which is my future direction as well.

Selected Publications:

Ouyang, Y., Xiang, Y., Zou, H. K., Chu, G. W., & Chen, J. F. (2017). Flow characteristics and micromixing modeling in a microporous tube-in-tube microchannel reactor by CFD. Chemical Engineering Journal, 321, 533-545.

Ouyang, Y., Zou, H. K., Gao, X. Y., Chu, G. W., Xiang, Y., & Chen, J. F. (2018). Computational fluid dynamics modeling of viscous liquid flow characteristics and end effect in rotating packed bed. Chemical Engineering and Processing: Process Intensification, 123, 185-194.

Ouyang, Y., Wang, S., Xiang, Y., Zhao, Z., Wang, J., & Shao, L. (2018). CFD analyses of liquid flow characteristics in a rotor-stator reactor. Chemical Engineering Research and Design, 134, 186-197.

Gao, X. Y., Chu, G. W., Ouyang, Y., Zou, H. K., Luo, Y., Xiang, Y., & Chen, J. F. (2017). Gas Flow Characteristics in a Rotating Packed Bed by Particle Image Velocimetry Measurement. Industrial & Engineering Chemistry Research, 56(48), 14350-14361.

Li, W. L., Ouyang, Y., Gao, X. Y., Wang, C. Y., Lei, S., & Xiang, Y. (2018). CFD analysis of gas-liquid flow characteristics in a microporous tube-in-tube microchannel reactor. Computers & Fluids.

Presented at conferences:

Ouyang, Y., Xiang, Y., Gao, X. Y., Zou, H. K., Chu, G. W., & Chen, J. F. Micromixing efficiency in a rotating packed bed with non-Newtonian fluids. in: The 17th Congress Of The Asian Pacific Confederation Of Chemical Engineering

Ouyang, Y., Xiang, Y., Gao, X. Y., Zou, H. K., Chu, G. W., & Chen, J. F. Micromixing efficiency optimization of premixed liquid distributor of rotating packed bed by CFD. in: The 8th Global Chinese Chemical Engineers Symposium