| Swirl atomizers have a great use in air-breathing gas turbine engines,especially in aerospace propulsion area,as they have excellent atomization features.Meanwhile,it is cheaper to manufacture swirl atomizers than other atomizers.To control emissions,it is essential to design some swirl atomizers that can produce spray with a particular droplet size distribution.Thus,the influence caused by different atomizer geometries should be well explored.In this dissertation,a new CFD software,XFlow,is utilized to predict the flow in swirl atomizers.This software is based on the Lattice Boltzmann method which is a mesoscopic way to describe the behavior of liquid and gas.This CFD code is validated with experimental data from the University of Cincinnati.The data agree well with experimental data for the film thickness at the exit,spray cone angle,and some other parameters.The numerical results are better than the results of empirical equations and theoretical methods.Using this software,XFlow,a particular study on swirl atomizer performance is proceeded.Different geometric parameters have been studied in this dissertation,such as the ratio of length to diameter in the swirl chamber(Ls/Ds),the ratio of length to diameter in orifice(lo/do)and the swirl chamber to orifice diameter ratio(Ds/do).The swirl chamber to orifice diameter ratio Ds/do has the greatest impact on atomization characteristics.The atomizer performance is detailed in term of film thickness at the exit(t),spray cone half angle(θ)and Sauter Mean Diameter(SMD).By analyzing these atomization characteristics,we can provide some suggestions on manufacturing swirl atomizers. |
