A coupled LBM-LES-DEM particle flow modeling for microfluidic chip and ultrasonic-based particle aggregation control method

Microfluidic chips present considerable potential in biomedical analysis and high-throughput cell separation, owing to their efficient and precise microscale flow control capabilities. In microscale channels, the highly nonlinear mechanics of vortex mixing and flow pattern evolution pose challenges to solid-liquid mass transfer modeling and particle cluster control. To address the above challenge, this paper proposes a two-phase particle flow modeling and ultrasonic-based particle aggregation control method for serpentine bionic microchannels in microfluidic chips. The particle flow dynamics model is established by coupling the lattice Boltzmann method (LBM) with the discrete element method (DEM), and integrating it with the large eddy simulation (LES) model. The LBM-LES-DEM model reveals the mixing and mass transfer mechanisms and particle distribution patterns in the serpentine channel under varying flow and particle conditions. Finally, utilizing an ultrasonic excitation strategy, the dispersion of particle distribution within the microchannels is significantly improved, and the fractal geometric dimension theory is used for quantitative characterization of the dispersion. This study demonstrates that the proposed modeling approach, combined with the ultrasonic excitation suppression strategy, effectively elucidates the mechanisms of flow field-particle mixing and mass transfer, as well as the evolution of particle flow patterns. The enhancement of turbulent characteristics in the flow field through ultrasonic excitation improves particle dispersion within the microchannels, effectively preventing particle deposition and agglomeration. Relevant results provide valuable insights into interphase interactions, cross-scale mass transfer, and particle distribution in microchannel flows, while providing technical support for optimizing mixing efficiency and dynamic processes in microfluidic chips.