Technical Paper
Effect of Spray Included Angle and Swirl Ratio on Combustion and Emissions under Post Injection
2021-09-21
2021-01-1169
The widespread application and increasingly stringent emission regulations call for more attention to optimize combustion process and emissions of marine diesel engine. This study conducts a numerical study to investigate the individual effect and their interaction of three post injection duration (3°CA, 5°CA and 7°CA), four spray included angles (145°, 150°, 155° and 160°) and four swirl ratios (0.5, 0.85, 1.2 and 1.6) in a marine diesel engine with main-post injection. These three parameters all exert impact on in-cylinder combustion performance and emissions by affecting fuel-air mixing quality. Results show that decreasing post injection duration from 7°CA to 3°CA shortens the combustion duration and decreases soot emission by 13.2%, while that induces a slight increase in NOx emissions by 1.0%. Spray included angle changes the spray targeting position within the combustion chamber.