Droplet Dynamics of Newtonian and Inelastic Non-Newtonian Fluids in Confinement
نویسندگان
چکیده
Microfluidic droplet technology has been developing rapidly. However, precise control of dynamical behaviour of droplets remains a major hurdle for new designs. This study is to understand droplet deformation and breakup under simple shear flow in confined environment as typically found in microfluidic applications. In addition to the Newtonian–Newtonian system, we consider also both a Newtonian droplet in a non-Newtonian matrix fluid and a non-Newtonian droplet in a Newtonian matrix. The lattice Boltzmann method is adopted to systematically investigate droplet deformation and breakup under a broad range of capillary numbers, viscosity ratios of the fluids, and confinement ratios considering shear-thinning and shear-thickening fluids. Confinement is found to enhance deformation, and the maximum deformation occurs at the viscosity ratio of unity. The droplet orients more towards the flow direction with increasing viscosity ratio or confinement ratio. In addition, it is noticed that the wall effect becomes more significant for confinement ratios larger than 0.4. Finally, for the whole range of Newtonian carrier fluids tested, the critical capillary number above which droplet breakup occurs is only slightly affected by the confinement ratio for a viscosity ratio of unity. Upon increasing the confinement ratio, the critical capillary number increases for the viscosity ratios less than unity, but decreases for the viscosity ratios more than unity.
منابع مشابه
Numerical Simulation of Non-Newtonian Inelastic Flows in Channel based on Artificial Compressibility Method
In this study, inelastic constitutive modelling is considered for the simulation of shear-thinning fluids through a circular channel. Numerical solutions are presented for power-law inelastic model, considering axisymmetric Poiseuille flow through a channel. The numerical simulation of such fluid is performed by using the Galerkin finite element approach based on artificial compression method (...
متن کاملBreakup dynamics and dripping-to-jetting transition in a Newtonian/shear-thinning multiphase microsystem.
The breakup dynamics in non-Newtonian multiphase microsystems is associated with a variety of industrial applications such as food production and biomedical engineering. In this study, we numerically and experimentally characterize the dripping-to-jetting transition under various flow conditions in a Newtonian/shear-thinning multiphase microsystem. Our work can help to predict the formation of ...
متن کاملRapid mixing of Newtonian and non-Newtonian fluids in a three-dimensional micro-mixer using non-uniform magnetic field
The mixing of Newtonian and non-Newtonian fluids in a magnetic micro-mixer was studied numerically using ferrofluid. The mixing process was performed in a three-dimensional steady-state micro-mixer. A magnetic source was mounted at the entrance of the micro-channel to oscillate the magnetic particles. The effects of electric current, inlet velocity, size of magnetic particles, and non-Newtonia...
متن کاملDetermination of Thermo-physical Properties of Non-Newtonian Fluids Using a Coaxial Cylindrical Cell
In this study the thermal conductivity and the volumetric heat capacity of non-Newtonian fluids are investigated. These fluids find many applications in chemical, medical and food industries. They mostly have viscoelastic behavior and generally differ from Newtonian fluids. Two non-Newtonian fluids, solutions of xanthan and carboxy methyl cellulose in water with various concentrations have bee...
متن کاملHeat Transfer of Liquid/ Solid Fluidized Beds for Newtonian and Non-Newtonian Fluids
The excellent performance of fluidized bed heat exchangers is due to the interaction between particles and heat transfer surface and to the mixing effects in the viscous sublayer. In this paper, the results of experimental investigations on heat transfer for a wide range of Newtonian and non-Newtonian (shear-thinning power law) fluids are presented. New design equations have been developed ...
متن کامل