扫气口角度和涡流比对船用柴油机性能的影响  

Effect of scavenge port angle and swirl ratio on performance of a marine diesel engine

作　　者：刘梦雨 鲁祯 朱峰 卢天龙 LIU Mengyu;LU Zhen;ZHU Feng;LU Tianlong(Shanghai Marine Diesel Engine Research Institute,Shanghai 201108,China;School of Mechanical Engineering,Tianjin University,Tianjin 300350,China)

机构地区：[1]中国船舶重工集团公司第七一一研究所,上海201108 [2]天津大学机械工程学院,天津300350

出　　处：《内燃机与动力装置》2023年第6期1-9,51,共10页Internal Combustion Engine & Powerplant

基　　金：国家自然科学基金面上项目(51976133)。

摘　　要：利用Converge软件建立某大缸径低速二冲程船用柴油机的三维数值仿真模型,仿真研究扫气口水平倾角对柴油机性能的影响,并解耦涡流比的单独影响机理。结果表明:扫气口水平倾角过大或过小均导致缸内产生回流区及新鲜空气过早溢出,降低扫气效率;与原机水平倾角为15°时相比,当扫气口水平倾角为10°时,有效燃油消耗率和NO_(x)排放均降低;在合理范围内增大涡流比可有效改善油气混合均匀性和燃烧过程;与原机涡流比为4.5时相比,涡流比为20.5时燃油消耗率降低5.09%,燃油经济性明显改善;但涡流比过大对燃油消耗率的改善较小,同时导致壁面传热损失较大,因此涡流比应控制在20.5以下。A three-dimensional numerical simulation model is established on the Converge software for a large-bore low-speed two-stroke marine diesel engine.The influence of the horizontal inclination angle of scavenging ports was studied,and the separate influence mechanism of swirl ratio was decoupled.The results show that scavenge ports angle affects the swirl ratio and scavenging efficiency.Excessive or insufficient horizontal inclination of scavenging ports create counterflow zones and lead to premature overflow of fresh air,which reduces the scavenging efficiency.When the angle of scavenging ports is 10°,the BSFC and NO x emissions are both reduced compared with the original machine with scavenging ports angle of 15°.Increasing the swirl ratio within a reasonable range can effectively improve the uniformity of oil-gas mixing and combustion process.Compared with the original engine with a swirl ratio of 4.5,when the swirl ratio is 20.5,the brake specific fuel consumption(BSFC)can reduce by 5.09%and the fuel economy has significantly improved.However,the excessive swirl ratio is relatively small for improvement of BSFC,and it is accompanied by a large amount of wall heat transfer loss,so the swirl ratio should be controlled below 20.5.

关 键 词：二冲程船用柴油机 扫气口角度 涡流比 燃烧 排放 

分 类 号：TK401[动力工程及工程热物理—动力机械及工程]