Spatially Optimized Multi-Shafts Stirred Reactors: An Experimental Study on Spatiotemporal Instabilities

Multi-shaft stirred reactors significantly impact the mixing efficiency and eliminate isolated mixed regions. Herein, the chaotic characteristics and spatiotemporal instability of flow fields were investigated in three different stirred reactor, and a novel flow field visualization technique was proposed to address limitations with low-viscosity fluids. Results demonstrated the chaotic behavior and energy transfer are inconsistent at various axial positions in the S-T-STR, D-T-STR, and T-T-STR flow fields, which are supported by pressure pulsation attractors, fractal dimension, largest Lyapunov exponents, multiscale entropy, and Kolmogorov entropy analysis. Torque signal attractor images confirmed stable periodic energy input to the flow field through the impeller. Hilbert spectrum analysis revealed time instability and periodic energy features after flow field stabilization. T-T-STR exhibited reduced spatial and temporal instability, denser periodic cycles, accelerated flow field structure evolution and energy transfer rate. These distinctions result from the distinctive flow field structure within each reactor configuration.