Ammonia,as a zero-carbon fuel,has great potential for meeting decarbonization targets in the internal combustion engine sector.This paper summarizes recent studies in which ammonia is used as a fuel for compressionign...Ammonia,as a zero-carbon fuel,has great potential for meeting decarbonization targets in the internal combustion engine sector.This paper summarizes recent studies in which ammonia is used as a fuel for compressionignition engines.Due to its low combustion reactivity,ammonia must be used in conjunction with a high reactivity fuel,such as diesel,to ensure stable engine operation.Currently,two main approaches are used to supply ammonia to the engine combustion chamber:ammonia port injection and in-cylinder direct injection.In the two routes,ammonia-diesel engines commonly face challenges such as low ammonia energy rate(AER),limited thermal efficiency,and high emissions of nitrogen-containing pollutants,especially under high ammonia substitution conditions.To address these challenges,this study reviews combustion technologies capable of achieving relatively high AER,such as premixed charge compression ignition(PCCI)and reaction-controlled compression ignition(RCCI),and analyzes their impact on combustion and emissions characteristics.This paper also examines combustion technologies under ultra-high AER conditions and finds that technologies such as diesel pilot injection and ammonia-diesel stratified injection can support stable engine operation.This review provides insights into current progress,remaining challenges,and future directions in ammonia-diesel engine combustion technologies.展开更多
As the low temperature non-equilibrium plasma,microwave plasma has the same effects with the plasma produced by the traditional high voltage electrode,which has the function of widening ignition boundary and improving...As the low temperature non-equilibrium plasma,microwave plasma has the same effects with the plasma produced by the traditional high voltage electrode,which has the function of widening ignition boundary and improving combustion.Microwave has the advantages of uniformity,particle selectivity and no electrode.It can generate a large range of non-equilibrium plasma with relatively low power without electrode ablation.Therefore,how to maximize its effectiveness has become the research hotspot of ignition and combustion in engines.At present,the related research mainly focuses on microwave plasma discharge and microwave assisted spark ignition.The results show that it can broaden lean and rich burn flammability limits,improve combustion efficiency,accelerate flame propagation speed,and reduce pollutant emissions.This paper summarizes the related research at home and abroad in recent years,the main conclusion is that how the microwave plasma affects the turbulence intensity of flow field will be the promising research,and the research trend of microwave plasma ignition and assisted combustion in future will be the research of microwave assisted plasma igniter.展开更多
With the objective of producing a full-scale tiny-oil ignition burner, identical to the burner used in an 800 MWe utility boiler, numerical simulations were performed using Fluent 6.3.26 to study the progress of ignit...With the objective of producing a full-scale tiny-oil ignition burner, identical to the burner used in an 800 MWe utility boiler, numerical simulations were performed using Fluent 6.3.26 to study the progress of ignition for four coal concentration settings covering sub- operation conditions prevailing during the experiments performed with the burner. The numerical simulations conformed to the experimental results, demonstrating the suitability of the model used in the calculations. Simula- tions for a coal concentration of 0.40 kg/kg corresponding to a single burner operating at its rated output were also conducted, which indicated that gas temperatures along the burner centerline were high. As gas flowed to the burner nozzle, the high-temperature region expanded, ensuring a successful pulverized-coal ignition. With increasing coal concentration （0.08-0.40 kg/kg）, the gas temperature along the burner centerline and at the first and second combustion chamber exits decreased at the equivalent radial points. At the center of the second combustion chamber exit, the O2 concentrations were almost depleted for the five coal concentrations, while the CO concentrations peaked.展开更多
The progression of ignition was numerically simulated with the aim of realizing a full-scale tiny-oil ignition burner that is identical to the burner used in an 800 MWe utility boiler. The numerical simulations were c...The progression of ignition was numerically simulated with the aim of realizing a full-scale tiny-oil ignition burner that is identical to the burner used in an 800 MWe utility boiler. The numerical simulations were conducted for four excess air ratios, 0.56, 0.75, 0.98 and 1.14 （corresponding to primary air velocities of 17, 23, 30 and 35 m/s, respectively）, which were chosen because they had been used previously in practical experiments. The numerical simulations agreed well with the experimental results, which demonstrate the suitability of the model used in the calculations. The gas temperatures were high along the center line of the burner for the four excess air ratios. The flame spread to the bumer wall and the high- temperature region was enlarged in the radial direction along the primary air flow direction. The O2 concentrations for the four excess air ratios were 0.5%, 1.1%, 0.9% and 3.0% at the exit of the second combustion chamber. The CO peak concentration was very high with values of 7.9%, 9.9%, 11.3% and 10.6% for the four excess air ratios at the exit of the second combustion chamber.展开更多
为了研究底排点火具在弹丸出炮口时瞬态燃烧特性及工作性能,采用半密闭爆发器模拟炮口压力突降过程,借助高速录像系统,开展了高降压速率条件下底排点火具燃烧特性的实验研究。结果表明,在高速降压过程中,底排点火具燃烧受到强烈瞬态扰...为了研究底排点火具在弹丸出炮口时瞬态燃烧特性及工作性能,采用半密闭爆发器模拟炮口压力突降过程,借助高速录像系统,开展了高降压速率条件下底排点火具燃烧特性的实验研究。结果表明,在高速降压过程中,底排点火具燃烧受到强烈瞬态扰动。不同药剂的点火具抗干扰性能不同,其中以硝酸钡为药剂主成分的点火具和以镁粉+PTFE为药剂主成分的点火具燃烧性能稳定,以氢化锆、二氧化铅为药剂主成分的点火具工作稳定性较差,火焰持续时间标准差为523 m s,点火具喷孔堵塞严重。展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2022YFE0209000)Science and Technology Commission of Shanghai Municipality,China(Grant Nos.22170712600,24120742400,and 24120750400)Science and Technology Revitalization Mongolia Action Plan of Shanghai Jiao Tong University and Shanghai Jiao Tong University-Wuxi Carbon-Neutrality Power Technology Research Institute.
文摘Ammonia,as a zero-carbon fuel,has great potential for meeting decarbonization targets in the internal combustion engine sector.This paper summarizes recent studies in which ammonia is used as a fuel for compressionignition engines.Due to its low combustion reactivity,ammonia must be used in conjunction with a high reactivity fuel,such as diesel,to ensure stable engine operation.Currently,two main approaches are used to supply ammonia to the engine combustion chamber:ammonia port injection and in-cylinder direct injection.In the two routes,ammonia-diesel engines commonly face challenges such as low ammonia energy rate(AER),limited thermal efficiency,and high emissions of nitrogen-containing pollutants,especially under high ammonia substitution conditions.To address these challenges,this study reviews combustion technologies capable of achieving relatively high AER,such as premixed charge compression ignition(PCCI)and reaction-controlled compression ignition(RCCI),and analyzes their impact on combustion and emissions characteristics.This paper also examines combustion technologies under ultra-high AER conditions and finds that technologies such as diesel pilot injection and ammonia-diesel stratified injection can support stable engine operation.This review provides insights into current progress,remaining challenges,and future directions in ammonia-diesel engine combustion technologies.
基金supported by the National Natural Science Foundation of China(No.51436008)。
文摘As the low temperature non-equilibrium plasma,microwave plasma has the same effects with the plasma produced by the traditional high voltage electrode,which has the function of widening ignition boundary and improving combustion.Microwave has the advantages of uniformity,particle selectivity and no electrode.It can generate a large range of non-equilibrium plasma with relatively low power without electrode ablation.Therefore,how to maximize its effectiveness has become the research hotspot of ignition and combustion in engines.At present,the related research mainly focuses on microwave plasma discharge and microwave assisted spark ignition.The results show that it can broaden lean and rich burn flammability limits,improve combustion efficiency,accelerate flame propagation speed,and reduce pollutant emissions.This paper summarizes the related research at home and abroad in recent years,the main conclusion is that how the microwave plasma affects the turbulence intensity of flow field will be the promising research,and the research trend of microwave plasma ignition and assisted combustion in future will be the research of microwave assisted plasma igniter.
基金sponsored by the Hi-Tech Research and Development Program of China （863 program） （Grant No. 2006AA05Z321） and supported by the Foundation for Innovative Research Groups of the National Natural Science Foundation of China （Grant No. 51121004）.
文摘With the objective of producing a full-scale tiny-oil ignition burner, identical to the burner used in an 800 MWe utility boiler, numerical simulations were performed using Fluent 6.3.26 to study the progress of ignition for four coal concentration settings covering sub- operation conditions prevailing during the experiments performed with the burner. The numerical simulations conformed to the experimental results, demonstrating the suitability of the model used in the calculations. Simula- tions for a coal concentration of 0.40 kg/kg corresponding to a single burner operating at its rated output were also conducted, which indicated that gas temperatures along the burner centerline were high. As gas flowed to the burner nozzle, the high-temperature region expanded, ensuring a successful pulverized-coal ignition. With increasing coal concentration （0.08-0.40 kg/kg）, the gas temperature along the burner centerline and at the first and second combustion chamber exits decreased at the equivalent radial points. At the center of the second combustion chamber exit, the O2 concentrations were almost depleted for the five coal concentrations, while the CO concentrations peaked.
文摘The progression of ignition was numerically simulated with the aim of realizing a full-scale tiny-oil ignition burner that is identical to the burner used in an 800 MWe utility boiler. The numerical simulations were conducted for four excess air ratios, 0.56, 0.75, 0.98 and 1.14 （corresponding to primary air velocities of 17, 23, 30 and 35 m/s, respectively）, which were chosen because they had been used previously in practical experiments. The numerical simulations agreed well with the experimental results, which demonstrate the suitability of the model used in the calculations. The gas temperatures were high along the center line of the burner for the four excess air ratios. The flame spread to the bumer wall and the high- temperature region was enlarged in the radial direction along the primary air flow direction. The O2 concentrations for the four excess air ratios were 0.5%, 1.1%, 0.9% and 3.0% at the exit of the second combustion chamber. The CO peak concentration was very high with values of 7.9%, 9.9%, 11.3% and 10.6% for the four excess air ratios at the exit of the second combustion chamber.
文摘为了研究底排点火具在弹丸出炮口时瞬态燃烧特性及工作性能,采用半密闭爆发器模拟炮口压力突降过程,借助高速录像系统,开展了高降压速率条件下底排点火具燃烧特性的实验研究。结果表明,在高速降压过程中,底排点火具燃烧受到强烈瞬态扰动。不同药剂的点火具抗干扰性能不同,其中以硝酸钡为药剂主成分的点火具和以镁粉+PTFE为药剂主成分的点火具燃烧性能稳定,以氢化锆、二氧化铅为药剂主成分的点火具工作稳定性较差,火焰持续时间标准差为523 m s,点火具喷孔堵塞严重。
