Delayed Detached Eddy Simulation of Spray Combustion in a Gas Turbine Combustor With and Without Nozzle Blockage

Abstract

Abstract. The performance of nozzles in the combustor is critical to the combustion process, and carbon deposition on the nozzles can significantly degrade combustion efficiency. Although many studies have been conducted on the spray combustion process under carbon-deposited nozzles, there is still a lack of coupling research on primary atomization and secondary atomization, as well as simulation research on the entire process from atomization to combustion. Therefore, this study first employed a hybrid atomization model combining volume of fluid (VOF) and discrete phase model (DPM), along with delayed detached eddy simulation (DDES) and eddy dissipation (ED), to conduct an unsteady numerical simulation of the entire process from atomization to combustion in the combustor with half of the nozzles blocked by carbon deposits. The results demonstrate that carbon deposits will cause deterioration of atomization and combustion performance: (1) the liquid film thickens and the spray cone angle decreases; (2) at the outlet of the radial swirl, the number of fuel droplets increases while their mean velocity is 21.8% higher than that of the normal nozzles; (3) the temperature distribution at the outlet of the combustor is uneven, with a temperature difference of 218 K. These results provide a feasible basis for exploring the influence of nozzle state on the spray combustion process by using the VOF-DPM hybrid atomization model and the ED model.