Numerical Simulation Of Viscosity Droplet's Formation And Deposit

Droplets are of interest in diverse applications. The formation and deposit of droplets involve complicated changes of liquid's shape, so it is not only a difficult theoretical problem but also important to experiments and product process. In order to know more about the droplets'evolvements and investigate the influences caused by the process, the droplet's formation and deposit on different substrates are studied in this paper by making use of numerical simulation method.The researches in this paper include the following four parts:1) Droplets'formation is numerical simulated. Taking the formation of glycerin solution of 60%, for example, the complete formation process is studied and explained from the points of velocities and pressures.2) Factors that influence the droplets'formation are numerically analyzed. In this paper, the influences of the real physical factors, boundary conditions and the diameter of the nozzle are studied. This is one of the innovations of this paper.3) Deposits of droplets for different velocities on diverse substrates are investigated. The droplets'diffusion is mainly complained from the aspects of energy, pressure and velocity. The collisions of droplets of high speed and low speed on substrates are simulated also. It is found that air entrainments can be caused in some cases and the touches of droplets can influence the film's quality.4) Numerical simulations of droplets'deposit on liquid film and solid substrates of different shapes are completed in the paper. The influences of droplets'velocities on the liquid film and the roughness of the substrate's surface on the droplets'deposit are studied. In the final chapter of the paper, the application of droplet ejection is introduced through the factures of thin film transistor. An effective method of confining the droplets'deposit is also investigated from the point of fluid dynamics.Doplets's formation and deposit are involved in many applications, and much attention is paid to this subject. The innovative results of this paper are presented in the following:1. It is summarized for influence of some real physical parameters on droplets'formation roundly in this paper, however, most foreign research papers in the field do emphasize the influence of non-dimentional factors such as Reynold number and Weir number.2. It is found in droplets'collision on the flat solid surface that the air entrainment can be encountered in the low speed collision and the contact among the neighbour droplets cause influences on the film in high speed collision. The result is not mentioned in publications now.3. It is focused on the mechanics problems involved in the manufactures of thin film transistors in this paper from the view of fluid dynamics. It is found that the droplet can be deposited normally only if the quality of the barrier, the droplets'speed and the space between the droplet and the barrier are in the proper collocation and the quality of the transistor could be ensured.It is shown that the method using in this paper is suitable to the investigaton of droplets'formation and deposit. The numerical simulation of droplets'formation and deposit is important to the application and benefits to the understanding of the mechanism, and also give references to the improvements of the droplets controlling system. The deposit quality could be predicted and defects may be found in advance by simulation of droplets'deposits. Also it will make the deposit meet the quality criteria based on the simulation by controlling the corresponded factors of droplets and surfaces.