Character Study On Air-blast Atomizer

The quality of spray mixing of the fuel-oil nozzle affects its burning character and discharging character directly, fuel oil ejecting itself is a dynamic course, and it is affected not only by structural style of nozzle and spray pressure, but also by the pressure, temperature, movement of air flow and so on in the combustion chamber.This thesis studies the atomization of Y-type fuel-oil nozzle by numerical simulation with CFD software-Fluent. This thesis overviews the development of nozzle and atomization theory, tells of the related knowledge about CFD to nozzle numerical simulation; Sets up and chooses the geometric model and mathematic model of Y-jet nozzle; fixes the best physical model and related set parameter of Y-jet nozzle; simulates the fuel oil atomization course and analyses the result. The numerical simulation is from several aspects as following:(1)This thesis analyses the ejecting orientation of atomization simulation, the gas-liquid two phase flow of the computational field and the spray field simply. And discusses the effect of the spray orientation of nozzle to atomization result, the disturbance of air flow velocity to gas-liquid two phase flow of the computational field, the distribution of the nozzle spray when the oil quantity is smaller.(2)This thesis studies the spray character of the nozzle from the operational parameter and structural parameter. The operational parameter mainly includes gas pressure,liquid pressure, gas-liquid two phase pressure ratio and the outlet pressure of the nozzle. The structural parameter mainly includes the gas hole diameter,the water hole diameter and the mixture hole diameter. Discusses the effect of their change to the spray character of the nozzle respectively. The simulation result indicates that they have their own effect rule to the spray character of the nozzle. But if the nozzle has very good spray quality, all the parameter must in a reasonable match.(3)This thesis analyses the spray droplet distribution of the downstream cross section and the gas phase flux character of the nozzle on the basis of the numerical simulation of the nozzle. The particle size distribution of the downstream cross section is axisymmetric, and the particle diameter distribution is very uniform. The gas phase flux of the nozzle changes along with the gas phase pressure of the nozzle and the configuration of the nozzle.