| The pressure swirl nozzle has advantages in simple structure, easy to manufacture and conveninet to spray. So, it is widely used in petroleum industry, chemical engineering, food, the desalination of sea water industries and so on.To study the effect of operating parameters and exit geometrical structures on spray characteristics. Numerical simulation has been applied.The study situation of nozzle at home and abroad has been summarized. The spray machanism of swirl nozzle has been introduced. Based on the related textual references, the swirl nozzle has been nemerically studied. Fristly, the three-dimensional model of swirl nozzle was setted up, the numerical simulation of the nozzle was done utilizing the FLUENT6.3. Used the VOF, the gas-liquid interface in and out of the nozzle was captured. The liquid film thickness at the outlet of nozzle was described. The influence of the export structure on liquid film thickness was analsed. Then extended the calculation area, the character of the distribution of the spray density, the influence of the export structure on distribution of the spray density was analsed.The result shows that the liquid film cling the inwall in the whirl room. There is an air cone in the central axis. The nearer it is to outlet, the larger the radius of air cone is and the thinner the liquid film thickness is. At the15mm below the outlet, the liquid volume fraction reduces to0.5, so the spray liquid has breoken fully to drop at this place. The bigger the diffusion angle is, the thinner the liquid filme is and the shorter the length of film broken is. The bigger the nozzle diameter is, the longer the length of film broken is, but the film thickness is unsteady, the size of film thickness is floating. The effect of the exit straight length is slight. With increase of the flow rate, the crest value of the spray density distribution move outward, and the cover area of spray liquid increase. The larger the diffusion angle is, the bigger the spray angle is, the area of spray liquid become bigger and the crest value become smaller, but the concentration ratio of density distribution become smaller. With increase of the nozzle diameters, the area of spray liquid move towards the direction of the radius increase, the crest value decrease and the concentration ratio also decrease. When the exit straight length increase, the area of spray liquid move towards the direction of the radius decrease, the crest value decrease slightly, the influence to the concentration ratio of density distribution is not obviously. |
PDF Full Text Request