Birleşik bir damlacığın düz bir zemine çarpma ve bu yüzeyde yayılması probleminin sayısal modellemesi

Impact and spreading of a compound viscous droplet on a substrate are studied computationally using front-tracking method as a model for single cell epitaxy, a technology developed to create 2D and 3D tissues cell by cell by printing cell-encapsulating droplets on a substrate using ink-jet printing method. The success of cell printing depends on cell viability during the printing process. In the present model, the cell is modeled as a highly viscous Newtonian droplet encapsulated by a less viscous liquid. Simulations are performed for a range of dimensionless parameters to probe deformation and rate of deformation of the cell, which are hypothesized to be the major cause of cell damage. It is found that deformation of inner droplet increases: as Reynolds number increases; as the diameter ratio of encapsulating droplet to cell decreases; as the ratio of surface tensions of air-solution interface to solution-cell interface increases; as the viscosity ratio of cell to encapsulating droplet decreases; or as the equilibrium contact angle decreases. It is observed that maximum deformation has local minimum at Weber number We = 2. Thereafter, effects of cell deformation on viability are estimated using the experimental correlation based on the data obtained by compressing cells between parallel plates. These results provide insight for optimal parameter ranges for maximal cell viability during printing. Finally the cell is modeled as a non-Newtonian fluid while other phases are assumed to be Newtonian. Oldroyd-B fluid is selected to reflect the viscoelasticity of the cell and some preliminary results are presented.