Atomization and Sprays, Vol.13, No.4, 373-393, 2003
Transient multidimensional modeling of air-blast atomizers
A group of models for representing air-blast atomization were tested together and compared to experimental data. A primary atomization model, known as the linearized instability sheet atomization (LISA) model, which was designed and validated for pressure-swirl atomization, has now been extended to air-blast atomizers. That model, presented and tested by Schmidt et al. [1], has been slightly modified in light of recent discoveries. Existing models for secondary breakup, droplet collision, and turbulent dispersion were used. None of these models was adjusted for better results, but they were instead tested for their predictive ability. The calculations were validated with two gas-turbine air-blast atomizers. The models were first applied to an injector typical of those used in small gas-turbine engines,for which both light-diffraction droplet-size distribution data and fuel flux distribution data were measured. Subsequently, the model was applied to simulate the flow from a fuel injector typical of those used in mid-thrust engines. In this case, laser velocimetry data were available for the gas phase, as well as drop size and mass flux data for the liquid phase. The laser velocimetry data provided a means to determine whether the underlying gas flow field was computed correctly, which is essential for modeling the spray accurately. Sensitivity to inputs and convergence criteria were also investigated. The agreement of the spray predictions with the experimental data was encouraging, which suggests that these models have general applicability for atomization. However, the results also indicate areas where the gas-phase calculation and spray models are lacking.