COMPUTATIONAL AND EXPERIMENTAL-STUDY OF LIQUID SHEET EMANATING FROM SIMPLEX FUEL NOZZLE

A computational model for flow in a simplex nozzle has been establishe d to predict the characteristics of the liquid sheet emanating from it , An important aspect of the numerical method is the accurate tracking of the liquid/gas interface. Because the interface geometry is not kn own a priori, it must be determined as part of the solution, The arbit rary-Lagrangian-Eulerian numerical method with finite volume formulati on was employed for this purpose, To validate the computational and nu merical modeling, experiments have been conducted on a large-scale noz zle using flow visualization techniques, The gas/liquid interface loca tions inside the nozzle, as well as just downstream of the orifice, ha ve been determined for a range of mass how rates and injector geometri es. Using these measurements, the liquid film thickness and angle of t he liquid sheet has been determined. Comparisons of the computational predictions with the experimental measurements show excellent agreemen t, Results indicate that the current theoretical correlations based on inviscid flow assumptions underestimate the film thickness and overes timate the spray angle significantly in large scale nozzles, It was fo und that an increase in the atomizer constant K [=A(p)/(D(m)d(o))] res ults in decreasing the spray angle and increasing the liquid film thic kness, where A(p) is the total swirl slot area, D-m is the effective s pin chamber diameter, and d(o) is the orifice diameter, The discharge coefficient also increases with the atomizer constant.