PDF(Pubmed)
Abstract：
The scavenging process significantly affects the combustion and emission performance of marine low-speed two-stroke dual-fuel engines. Optimizing scavenging air pressure and temperature can enhance the engine\'s combustion efficiency and emission control performance, thereby achieving more environmentally friendly and efficient operation of dual-fuel engines. This study focuses on marine low-speed two-stroke dual-fuel engines, analyzing the effects of scavenging air pressure (3.0 bar, 3.25 bar, 3.5 bar, and 3.75 bar) and scavenging air temperature (293 K, 303 K, and 313 K) on engine performance and emission products. The results indicate that scavenging air pressure has a greater impact on engine performance than scavenging air temperature. An increase in scavenging air pressure leads to higher thermal efficiency and power. As the scavenging air pressure increases from 3 to 3.75 bar, the indicated thermal efficiency (ITE) increases from 44.02 to 53.26%, and indicated mean effective pressure (IMEP) increases by approximately 0.35 MPa. Increased scavenging air pressure improves nitrogen oxide (NOx) and hydrocarbons (HC) emissions. For every 0.25 bar increase in scavenging air pressure, NOx emissions decrease by 3.53%, HC emissions decrease by 33.35%, while carbon dioxide (CO2) emissions increase by 0.71%. An increase in scavenging air temperature leads to lower ITE and IMEP. As the air temperature changes from 293 to 313 K, the ITE decreases by approximately 1%, and IMEP decreases by about 0.04 MPa. Increased scavenging air temperature improves CO2 emissions. For every 10 K increase in the air temperature, the CO2 emissions decrease by 0.02%, while NOx emissions increase by 4.84%, HC emissions increase by 34.39%. Therefore, controlling scavenging air pressure is more important than scavenging air temperature in the operational management of marine two-stroke engines. Higher power and lower NOx and HC emissions can be achieved by increasing the scavenging air pressure.
摘要：
扫气过程显著影响船用低速二冲程双燃料发动机的燃烧和排放性能。优化扫气压力和温度可以提高发动机的燃烧效率和排放控制性能,从而实现双燃料发动机更加环保和高效的运行。本研究主要针对船用低速二冲程双燃料发动机,分析扫气压力的影响(3.0巴，3.25bar,3.5bar,和3.75巴)和扫气空气温度(293K，303K,和313K)对发动机性能和排放产品的影响。结果表明，与扫气温度相比，扫气压力对发动机性能的影响更大。扫气空气压力的增加导致更高的热效率和功率。当扫气压力从3巴增加到3.75巴时，指示热效率(ITE)从44.02增加到53.26%，指示平均有效压力(IMEP)增加约0.35MPa。增加的扫气空气压力改善了氮氧化物(NOx)和碳氢化合物(HC)的排放。扫气压力每增加0.25bar,NOx排放量下降3.53%,HC排放量减少33.35%,二氧化碳（CO2）排放量增加0.71％。扫气温度的升高导致较低的ITE和IMEP。当空气温度从293到313K变化时，ITE减少约1%，IMEP降低约0.04MPa。提高的扫气温度改善了CO2排放。空气温度每升高10K,二氧化碳排放量减少了0.02%，NOx排放量增加了4.84%，HC排放量增加34.39%。因此,在船用二冲程发动机的运行管理中，控制扫气压力比控制扫气温度更为重要。通过增加扫气空气压力可以实现更高的功率和更低的NOx和HC排放。
