Optimization Research on Main Stage Atomizer Structure of Marine Low Emission Tower-Type Coaxial-Staged Combustor

In order to satisfy the demand of pollutant emissions for marine gas turbine, the low emission tower-type coaxial-staged combustor was designed and its main stage atomizer structure was optimized. The flow field characteristics and performance parameters of combustor were studied under different atomizer structures by numerical simulation. Results show that when plain orifice atomizer is replaced with plain-jet airblast atomizer in main stage, the carbon deposits on the wall of swirler are avoided and fuel-air mixing characteristics are improved. At combustor outlet, the quality of temperature distribution is improved, NO and CO emissions are decreased by 71.4% and 60%, respectively. As for plain-jet airblast atomizer, the ratio of the height between the fuel tube end and atomizer exit orifice to its inner diameter(H/D)has a much higher impact on fuel-air mixing characteristics and temperature distribution in combustor than its air exit geometry. When H/D is too large or too small, the fuel-air mixing level will deteriorate and pollutant emissions will increase. The radial temperature distribution coefficient at combustor outlet decreases with the increase of H/D. Based on the comprehensive analysis of fuel-air mixing characteristics, temperature distribution and performance parameter of combustor, the cylindrical air exit geometry and H/D=2 is determined for optimal atomizer. © 2022 Journal of Propulsion Technology. All rights reserved.