扫气压力对船用天然气/柴油双燃料发动机燃烧排放的影响
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摘要
为研究扫气压力对缸内直喷船用双燃料发动机燃烧排放特性的影响规律,在通过试验数据对模型验证的基础上,采用有限容积法进行燃烧过程方程组的离散,同时采用半隐式法进行多变量耦合数值求解,分别就船用天然气/柴油双燃料发动机不同扫气压力对发动机缸内压力、缸内温度、缸内湍流和排放产物的影响进行了数值计算。结果表明:扫气压力的提高可导致缸内最大爆压增大,缸内最高温度与缸内湍流动能峰值降低;同时NO和CH~4排放量均随扫气压力的提高呈下降趋势;扫气压力每提高0.25 bar,缸内最大爆压平均升高5%,而缸内最高温度平均降低2.5%,缸内湍流动能峰值平均降低6.9%,NO排放量减少7.8%,CH~4排放量减少10.9%,扫气压力对CH~4排放的影响比对NO排放的影响更明显。研究表明,船用天然气/柴油双燃料发动机在运行过程中,应在发动机热负荷允许的范围内,尽可能采用高的扫气压力,以降低未燃CH~4和NO的排放,从而提升发动机的动力性和经济性。
Dual fuel engine has become an important development trend of marine engines. In order to further understand the influence of scavenging pressure on combustion characteristics of marine natural gas/diesel dual fuel engine,on the basis of experimental verification,the finite volume method was adopted to discrete the equations of the combustion process,and the semi-implicit method was adopted to solve the multivariable coupling numerical analysis. The effect of different scavenging pressure on combustive pressure,temperature,turbulence intensity in a cylinder,and emission of the engine were investigated. The results showed that the increase in the scavenging pressure increased the peak cylinder pressure,but decreased the peak temperature and peak cylinder turbulent kinetic energy. NO and CH~4 emission was decreased with the increase in the scavenging pressure in the meantime. It was found that,with increase in scavenging pressure every 0. 25 bar,the peak cylinder pressure respectively rose by5%,while peak temperature,peak cylinder turbulent kinetic energy,NO emissions and CH~4 emissions was reduced by 2.5%,6.9%,7.8% and 10.9%,respectively. The effect of scavenging pressure on CH~4 emission was more pronounced than that on NO emission. Therefore,the marine natural gas/diesel dual fuel engine should be use high scavenging pressure as far as possible,within the allowable range of engine heat load in the work condition,to reduce unburned CH~4 and NO emissions,for enhancing the power and economy of an engine.
Dual fuel engine has become an important development trend of marine engines. In order to further understand the influence of scavenging pressure on combustion characteristics of marine natural gas/diesel dual fuel engine,on the basis of experimental verification,the finite volume method was adopted to discrete the equations of the combustion process,and the semi-implicit method was adopted to solve the multivariable coupling numerical analysis. The effect of different scavenging pressure on combustive pressure,temperature,turbulence intensity in a cylinder,and emission of the engine were investigated. The results showed that the increase in the scavenging pressure increased the peak cylinder pressure,but decreased the peak temperature and peak cylinder turbulent kinetic energy. NO and CH~4 emission was decreased with the increase in the scavenging pressure in the meantime. It was found that,with increase in scavenging pressure every 0. 25 bar,the peak cylinder pressure respectively rose by5%,while peak temperature,peak cylinder turbulent kinetic energy,NO emissions and CH~4 emissions was reduced by 2.5%,6.9%,7.8% and 10.9%,respectively. The effect of scavenging pressure on CH~4 emission was more pronounced than that on NO emission. Therefore,the marine natural gas/diesel dual fuel engine should be use high scavenging pressure as far as possible,within the allowable range of engine heat load in the work condition,to reduce unburned CH~4 and NO emissions,for enhancing the power and economy of an engine.
引文
[1]China Classification Society.CCS Guideline 36:2011 Guidelines for testing and survey of emission of nitrogen oxides from marine diesel engines[S].[S.l.]:China Classification Society,2011.
[2]IMO.Amendments to the revised AnnexⅥof MARPOL73/78 Convention-prevention of air pollution from ships rule[S].IMO,2010.
[3]Di Natale F,Carotenuto C.Particulate matter in marine diesel engines exhausts:emissions and control strategies[J].Transportation Research Part D:Transport and Environment,2015,40:166-191.
[4]Brynolf S,Fridell E,Andersson K.Environmental assessment of marine fuels:liquefied natural gas,liquefied biogas,methanol and Bio-methanol[J].Journal of Cleaner Production,2014,74:86-95.
[5]孙慧慧,王天友,张海岩.高压缩比稀薄燃烧天然气发动机的燃烧与排放特性[J].天然气工业,2013,33(2):90-94.
[6]李斌.船舶柴油机[M].2版.大连:大连海事大学出版社,2014.
[7]姜国栋,朱庚生,冯丽珠,等.直流扫气二冲程内燃机的扫气流动数值模拟和性能预测[J].内燃机学报,1990,8(3):269-278.
[8]马富康,赵长禄,赵振峰,等.对置活塞二冲程汽油机直流扫气系统参数研究[J].内燃机工程,2016,37(5):152-159.
[9]张栓录,赵长禄,赵振峰,等.液压自由活塞发动机直流扫气设计及优化研究[J].内燃机工程,2016,37(6):110-115.
[10]邹玉红,卢勇,裴普成,等.双对置二冲程柴油机扫气过程的进气口结构影响规律[J].西安交通大学学报,2016,50(1):47-52.
[11]王志,徐雅齐,王建昕,等.增压直喷汽油机扫气抑制爆震试验研究及模拟解析[J].内燃机工程,2013,34(4):13-17.
[12]章振宇,赵长禄,张付军,等.对置活塞二冲程柴油机扫气系统优化方法研究[J].内燃机工程,2015,36(5):90-95.
[13]宋义忠,胡玮,石磊,等.增压GDI发动机全负荷工况扫气特性及气门正时策略优化研究[J].车用发动机,2014(4):49-54.
[14]董雪飞,赵长禄,赵振峰.进排气压力对增压对置活塞二冲程发动机的影响研究[J].内燃机工程,2016,37(4):28-32.
[15]于洪亮,段树林,孙培廷.主/引定时对船用天然气/柴油双燃料发动机燃烧排放的影响[J].推进技术,2016,37(9):1735-1741.
[16]郑清平.压燃式天然气发动机燃烧过程模拟计算和试验研究[D].天津:天津大学,2006.
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[18]Abianeh O S,Chen C P,Mahalingam S.Modeling of multi-component droplet coalescence in evaporating and non-evaporating diesel fuel sprays[J].International Journal of Automotive Technology,2014,15(7):1091-1100.
[19]Zsély I G,Nagy T,Simmie J M,et al.Reduction of a detailed kinetic model for the ignition of methane/propane mixtures at gas turbine conditions using simulation error minimization methods[J].Combustion and Flame,2011,158(8):1469-1479.
[20]解茂昭.内燃机计算燃烧学[M].大连:大连理工大学出版社,2005.
[21]刘戈,解茂昭,贾明.利用RIF模型对内燃机燃烧过程的模拟[J].内燃机学报,2011,29(5):398-404.
[22]何学良,李疏松.内燃机燃烧学[M].北京:机械工业出版社,1990.
[23]于洪亮,段树林,孙培廷.LNG气化温度对船用天然气/柴油双燃料发动机燃烧排放的影响[J].推进技术,2015,36(9):1369-1375.
[24]Yu H L,Duan S L,Sun P T.Comparative analysis between natural gas/diesel(dual fuel)and pure diesel on the marine diesel engine[J].Journal of Engineering Research,2015,3(4):111-125.
[2]IMO.Amendments to the revised AnnexⅥof MARPOL73/78 Convention-prevention of air pollution from ships rule[S].IMO,2010.
[3]Di Natale F,Carotenuto C.Particulate matter in marine diesel engines exhausts:emissions and control strategies[J].Transportation Research Part D:Transport and Environment,2015,40:166-191.
[4]Brynolf S,Fridell E,Andersson K.Environmental assessment of marine fuels:liquefied natural gas,liquefied biogas,methanol and Bio-methanol[J].Journal of Cleaner Production,2014,74:86-95.
[5]孙慧慧,王天友,张海岩.高压缩比稀薄燃烧天然气发动机的燃烧与排放特性[J].天然气工业,2013,33(2):90-94.
[6]李斌.船舶柴油机[M].2版.大连:大连海事大学出版社,2014.
[7]姜国栋,朱庚生,冯丽珠,等.直流扫气二冲程内燃机的扫气流动数值模拟和性能预测[J].内燃机学报,1990,8(3):269-278.
[8]马富康,赵长禄,赵振峰,等.对置活塞二冲程汽油机直流扫气系统参数研究[J].内燃机工程,2016,37(5):152-159.
[9]张栓录,赵长禄,赵振峰,等.液压自由活塞发动机直流扫气设计及优化研究[J].内燃机工程,2016,37(6):110-115.
[10]邹玉红,卢勇,裴普成,等.双对置二冲程柴油机扫气过程的进气口结构影响规律[J].西安交通大学学报,2016,50(1):47-52.
[11]王志,徐雅齐,王建昕,等.增压直喷汽油机扫气抑制爆震试验研究及模拟解析[J].内燃机工程,2013,34(4):13-17.
[12]章振宇,赵长禄,张付军,等.对置活塞二冲程柴油机扫气系统优化方法研究[J].内燃机工程,2015,36(5):90-95.
[13]宋义忠,胡玮,石磊,等.增压GDI发动机全负荷工况扫气特性及气门正时策略优化研究[J].车用发动机,2014(4):49-54.
[14]董雪飞,赵长禄,赵振峰.进排气压力对增压对置活塞二冲程发动机的影响研究[J].内燃机工程,2016,37(4):28-32.
[15]于洪亮,段树林,孙培廷.主/引定时对船用天然气/柴油双燃料发动机燃烧排放的影响[J].推进技术,2016,37(9):1735-1741.
[16]郑清平.压燃式天然气发动机燃烧过程模拟计算和试验研究[D].天津:天津大学,2006.
[17]AVL FIRE.AVL FIRE v2008缸内计算控制参数说明[M].Austria:AVL LIST,2008.
[18]Abianeh O S,Chen C P,Mahalingam S.Modeling of multi-component droplet coalescence in evaporating and non-evaporating diesel fuel sprays[J].International Journal of Automotive Technology,2014,15(7):1091-1100.
[19]Zsély I G,Nagy T,Simmie J M,et al.Reduction of a detailed kinetic model for the ignition of methane/propane mixtures at gas turbine conditions using simulation error minimization methods[J].Combustion and Flame,2011,158(8):1469-1479.
[20]解茂昭.内燃机计算燃烧学[M].大连:大连理工大学出版社,2005.
[21]刘戈,解茂昭,贾明.利用RIF模型对内燃机燃烧过程的模拟[J].内燃机学报,2011,29(5):398-404.
[22]何学良,李疏松.内燃机燃烧学[M].北京:机械工业出版社,1990.
[23]于洪亮,段树林,孙培廷.LNG气化温度对船用天然气/柴油双燃料发动机燃烧排放的影响[J].推进技术,2015,36(9):1369-1375.
[24]Yu H L,Duan S L,Sun P T.Comparative analysis between natural gas/diesel(dual fuel)and pure diesel on the marine diesel engine[J].Journal of Engineering Research,2015,3(4):111-125.