We numerically study the dynamics of particle crystals in annular microchannels by the immersed-boundary（IB）lattice Boltzmann（LB） coupled model, analyze the fluid-particle interactions during the migration of part...We numerically study the dynamics of particle crystals in annular microchannels by the immersed-boundary（IB）lattice Boltzmann（LB） coupled model, analyze the fluid-particle interactions during the migration of particles,and reveal the underlying mechanism of a particle focusing on the presence of fluid flows. The results show that the Reynolds and Dean numbers are key factors influencing the hydrodynamics of particles. The particles migrate onto their equilibrium tracks by adjusting the Reynolds and Dean numbers. Elliptical tracks of particles during hydrodynamic focusing can be predicted by the IB-LB model. Both the small Dean number and the small particle can lead to a small size of the focusing track. This work would possibly facilitate the utilization of annular microchannel flows to obtain microfluidic flowing crystals for advanced applications in biomedicine and materials synthesis.展开更多
Flow profiles are frequently engineered in microfluidic channels for enhanced mixing,reaction control,and material synthesis.Conventionally,flow profiles are engineered by inducing inertial secondary flow to redistrib...Flow profiles are frequently engineered in microfluidic channels for enhanced mixing,reaction control,and material synthesis.Conventionally,flow profiles are engineered by inducing inertial secondary flow to redistribute the streams,which can hardly be reproduced in microfluidic environments with negligible inertial flow.The employed symmetric channel structures also limit the variety of achievable flow profiles.Moreover,each of the flow profiles specifically corresponds to a strictly defined flow condition and cannot be generalized to other flow environments.To address these issues,we present a systematic method to engineer the flow profile using inertialess secondary flow.The flow is manipulated in the Stokes regime by deploying a cascaded series of microsteps with various morphologies inside a microchannel to shape the flow profile.By tuning the shapes of the microsteps,arbitrary outflow profiles can be customized.A numerical profile-transformation program is developed for rapid prediction of the output profiles of arbitrary sequences of predefined microsteps.The proposed method allows the engineering of stable flow profiles,including asymmetric ones,over a wide range of flow conditions for complex microfluidic environmental prediction and design.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 51728601 and 51771118the Natural Science Foundation of Jiangsu Province under Grant No BK20150600
文摘We numerically study the dynamics of particle crystals in annular microchannels by the immersed-boundary（IB）lattice Boltzmann（LB） coupled model, analyze the fluid-particle interactions during the migration of particles,and reveal the underlying mechanism of a particle focusing on the presence of fluid flows. The results show that the Reynolds and Dean numbers are key factors influencing the hydrodynamics of particles. The particles migrate onto their equilibrium tracks by adjusting the Reynolds and Dean numbers. Elliptical tracks of particles during hydrodynamic focusing can be predicted by the IB-LB model. Both the small Dean number and the small particle can lead to a small size of the focusing track. This work would possibly facilitate the utilization of annular microchannel flows to obtain microfluidic flowing crystals for advanced applications in biomedicine and materials synthesis.
基金This work was supported by the General Research Fund(17306315,17304017,and 17305518)and Research Impact Fund(R7072-18)from the Research Grants Council(RGC)of Hong Kong,Chinathe Excellent Young Scientists Fund(Hong Kong and Macao)(21922816)from the National Natural Science Foundation of China(NSFC)+1 种基金the Seed Funding for Strategic Interdisciplinary Research Scheme 2017/18 from the University of Hong Kongas well as the Sichuan Science and Technology Program(2018JZ0026).
文摘Flow profiles are frequently engineered in microfluidic channels for enhanced mixing,reaction control,and material synthesis.Conventionally,flow profiles are engineered by inducing inertial secondary flow to redistribute the streams,which can hardly be reproduced in microfluidic environments with negligible inertial flow.The employed symmetric channel structures also limit the variety of achievable flow profiles.Moreover,each of the flow profiles specifically corresponds to a strictly defined flow condition and cannot be generalized to other flow environments.To address these issues,we present a systematic method to engineer the flow profile using inertialess secondary flow.The flow is manipulated in the Stokes regime by deploying a cascaded series of microsteps with various morphologies inside a microchannel to shape the flow profile.By tuning the shapes of the microsteps,arbitrary outflow profiles can be customized.A numerical profile-transformation program is developed for rapid prediction of the output profiles of arbitrary sequences of predefined microsteps.The proposed method allows the engineering of stable flow profiles,including asymmetric ones,over a wide range of flow conditions for complex microfluidic environmental prediction and design.
