| Bacilli are a class of rod-shaped bacteria with a length of 0.2-5 microns,composed of cell walls and cell membranes surrounding the cytosol and cytoplasm.Cell walls and cell membranes have the physical characteristics of incompressibility and low flexural modulus,and are prone to deformation when subjected to external forces.The unique structure and physical properties of bacilli play an important role in human diseases,animal and plant life activities and the formation of inorganic substances.With the deepening of research,the flow adsorption kinetics of bacilli on the surface has attracted extensive attention.The long axis of the bacillus is a,the short axis is b,the height h and the distance d of the rough surface obstacle.In this paper,a finite element numerical simulation study of the dynamic behavior of bacilli on rough surfaces in steady state and oscillatory shear flow is carried out.The main research contents are divided into two parts:1.Kinetic behavior of bacilli on rough surfaces in steady-state shear flow: The effects of shear rate,initial position,initial angle,obstacle height and density on the movement patterns of viscoelastic bacilli are described.The results show that the bacilli have three motion modes of adsorption,slip and desorption on the rough surface;the motion mode of the bacilli is mainly affected by the shear rate and the height of the obstacle on the rough surface.When the obstacle height h=1.2 μm,the shear rate Whenγ<0.2/s,the fluid lift of the bacillus is less than its own gravity,and its bottom is in contact with the rough surface,so as to stabilize the adsorption;when the shear rate is0.2≤γ<0.6/s,the fluid lift of the bacillus can be balanced with its own gravity.,so the adsorption movement of the bacilli is inhibited and the bacilli are in the state of slip movement;when the shear rate γ≥0.6/s,the slip state no longer appears,only the desorption state.2.Kinetic behavior of bacilli on rough surfaces in oscillating shear flow: The effects of shear frequency,shear amplitude,initial position,initial angle,obstacle height and density on the movement of bacilli are described.The results show that the movement modes of bacilli include adsorption,slippage and desorption.The shear frequency and the height of obstacles on the rough surface are the main factors affecting the movement form of bacilli.In tangential flow,when the shear frequency f <0.2Hz,the height of the rough surface obstacle is in the range of 0≤h≤6b(the long axis of the bacillus is a,the short axis is b),and there are three forms of movement of the bacilli,namely adsorption,Slippage and desorption;when the shear frequency f≥0.2Hz,the height of the obstacle on the rough surface is in the range of 0≤h≤6b,and there are two forms of bacillus movement,namely adsorption and desorption.The increase of the shear frequency severely inhibited the two movement modes of wall slippage and detachment from the wall surface,making the bacilli more inclined to stably adsorb.In this paper,the effects of shear rate changes and rough surface differences on the kinetic behavior of bacilli are described in detail,and the relevant kinetic phase diagrams are enriched and developed for the preparation and application of bacillus microcapsules in biomedical devices such as antibacterial,bacterial infection,and bacillus microcapsules.The process provides reliable theoretical guidance. |
