Intensification of micromixing efficiency in a spinning disk reactor: Experimental investigation

A premixer and grooved surface are designed to improve the micromixing performance of a spinning disc reactor (SDR). The inlets of the impinging jet provide an initial premixing of the two streams. The effects of premixing and grooved surface on the overall micromixing performance at different conditions are investigated systematically. The results show that premixing and trapezoidal groove surface could greatly intensify the global micromixing performance of SDR. Increasing the rotation speed and flow rate also significantly improves the micromixing effect. When the disc distance is lower than 0.80 mm, an extremely low inter disc distance deteriorates the micromixing. The effect of premixing on the micromixing performance of low viscosity streams is more significant than that of the spinning disc itself. However, for high viscosity streams, the micromixing performance strongly depends on the spinning disc. The flow patterns in the designed SDR were further studied. Three flow patterns, including film flow, film− filament transitional flow, and filament flow, were observed in SDR with a stator disc. High rotational speed, large disc spacing, and low volumetric flow rate are conducive to the formation of filament flow rather than film flow. Predicative dimensionless criteria for flow patterns were established. The results provide meaningful information for further intensifying the micromixing performance of SDR.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Configuration of a Premixer and Grooved Surface to Intensify the Micromixing Performance of a Spinning Disc Reactor

Tang,

Zhang,

et al. 2024

“…As molecular scale mixing performance has impact on many reaction processes, micromixing could determine whole process cost and product quality especially for many fast reactions . Due to the significance of mixing, various mixing intensification devices have been developed, − among which micromixers are promising for acquiring excellent mixing quality …”

Section: Introductionmentioning

confidence: 99%

Micromixing Performance and Residence Time Distribution in a Miniaturized Magnetic Reactor: Experimental Investigation and Machine Learning Modeling

Chen

Deng

Luo

2023

Miniaturization of mixers is a hot topic in process intensification, but efficient mixing at operational conditions with relatively large viscosity μ and large flow rate ratio R between two mixed solutions is still a great challenge for micromixers. Herein, a miniaturized magnetic reactor (MMR) is developed, and its micro- and macromixing performances are characterized by the Villermaux/Dushman reaction and residence time distribution experiments, respectively. The results show that the miniaturization of the premixing unit and the stirred unit is vital. By arranging the stirred units in series, the MMR is effective in reducing axial dispersion, intensifying mixing at operational conditions with large μ and R and achieving efficient energy utilization without introducing extra energy input. The micromixing time t m in the optimized MMR ranges from 0.24 to 1.42 ms when 4.72 mPa·s < μ < 73.30 mPa·s and 8 < R < 20, indicating superior micromixing performance. Moreover, machine learning models are established and compared for predicting t m with excellent accuracy and guiding mixer design, and the SHAP method is adopted for model interpretation.

“…When the characteristic micromixing time is larger than the characteristic reaction time in a device, the micromixing performance plays a crucial role in the product yield and selectivity of the reaction. Therefore, various devices for micromixing process intensification have been proposed, − and among which, micromixers with a characteristic size scale from micrometer to millimeter exhibit excellent micromixing performance. , Micromixers possess large specific surface areas and very short mixing distances . Many recent reviews present state-of-the-art micromixers. − …”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Investigation on the Scaling-Up of Microsieve Dispersion Mixers

Chen

Wang

et al. 2022

Scaling-up is a significant topic for micromixers and their industrialized applications. In this work, the scaling-up of microsieve dispersion mixers (MDMs) is systematically investigated. Two scaling-up ways, including sizing-up of the main channel or the microsieve and numbering-up of microsieves, are studied. The mixing performance is characterized by experiments as well as CFD simulation. The results show that the preference of sizing-up dimensions to optimize the micromixing performance at a low flow rate ratio (R, R = 1) is contrary to that of a high R (R = 8) for both sizing-up choices. Numbering-up of microsieves is superior to sizing-up of microsieves, and numbering up in the l 1 direction is preferred. Equivalent micromixing performance can be maintained as long as the Reynolds number is kept constant during scaling-up. Two flow patterns including unrestricted and restricted flows are observed, which account for the difference in micromixing performance, and are distinguished by a dimensionless number. A mathematical model is established and used to predict the micromixing performance. Moreover, a design procedure for scaling up of MDMs is proposed.