Comprehensive Fuel Spray Modeling and Impacts on Chamber Acoustics in Combustion Dynamics Simulations

The current study focuses on comprehensive fuel spray modeling and its effects on chamber acoustics in combustion dynamics simulations. The fuel spray is modeled using an Eulerian-Lagrangian approach describing the atomizer internal flow, primary atomization, and secondary atomization processes. To anchor the fuel spray model, a series of experiments has been conducted on the fuel atomizer with and without co-flowing air. Spray cone angle, drop-size and velocity distributions were obtained using a high speed camera and Phase Doppler Anemometry (PDA). The fuel spray model results show reasonable agreement with the measured spray cone angles. The computed drop size and velocity distribution however indicate some discrepancies compared with the experimental results suggesting model limitations in describing secondary atomization. In addition, effects of fuel spray modeling on chamber acoustics are studied using combustion dynamics simulations. Three fuel spray models—specified drop size distribution, single droplet injection and hollow-cone injection—have been used. Among the three models, the hollow cone injected fuel spray shows good qualitative comparison of chamber acoustics with the experimental results. The pressure fluctuation amplitudes from the simulation, however, underestimate the measured amplitudes. Insufficient description of secondary atomization in the spray model appears to be a critical factor that leads to the observed discrepancies in the fuel spray and combustion dynamics simulations. ∗Corresponding Author: [email protected] Distribution Statement A: Approved for public release; distribution is unlimited.