An Accurate and Affordable Spray Model for Gas Turbine Combustor Design Available to Purchase

The mode of fuel preparation, the method of injection into a combustor and its atomization characteristics have a significant impact on emissions. A simple dilute spray model which assumes sequential droplet heating and vaporization has been implemented in the past within computational fluid dynamics (CFD) codes at GE and has been used extensively for combustion applications. This spray model coupled with an appropriate combustion model makes reasonable predictions of the combustor pattern factor and emissions. In order to improve upon this predictive ability, a more advanced quasi-steady droplet vaporization model has been considered. This approach that accounts for simultaneous droplet heating and vaporization, using an infinite-conductivity model, and is therefore more realistic has been described in an earlier paper (Tolpadi et al., 1999). In the present study, the droplet submodels used for the computation of droplets’ trajectories and vaporization histories have been improved. The transient liquid-phase transport is represented by the conduction-limit and effective-conductivity models, the drag coefficient correlation is modified to account for the effect of droplet vaporization, the variable thermophysical properties of both liquid and gas phases are considered, and the high-pressure effects are included. Validation of this new approach for a single droplet was initially performed. Subsequently, calculations of the flow and temperature field were conducted and emissions (NOx, CO and UHC) were predicted for a modern single annular turbofan engine combustor using all the aforementioned droplet modeling approaches.