The EGR (exhaust gas recirculation) technique can greatly reduce the NOx emission of diesel engines, especially when an EGR cooler is employed. Numerical simulations are applied to study the flow field and temperature...The EGR (exhaust gas recirculation) technique can greatly reduce the NOx emission of diesel engines, especially when an EGR cooler is employed. Numerical simulations are applied to study the flow field and temperature distributions inside the EGR cooler. Three different models of EGR cooler are investigated, among which model A is a traditional one, and models B and C are improved by adding a helical baffle in the cooling area. In models B and C the entry directions of cooling water are different, which mostly influences the flow resistance. The results show that the improved structures not only lengthen the flow path of the cooling water, but also enhance the heat exchange rate between the cool and hot media. In conclusion we suggest that the improved structures are more powerful than the traditional one.展开更多
An acid-free dissolution rare-earth magnet recycling process has earned a 2018 Notable Technology Development Award from the Federal Laboratories Consortium （FLC）.
建立了氢内燃机一维模型,分别仿真分析了废气再循环(exhaust gas recirculation,EGR)技术和米勒循环技术对抑制爆震及氮氧化物(NO_(x))排放的效果,最后结合两种技术探索了可达到的最大压缩比和最好的NO_(x)排放性能。结果显示EGR技术对...建立了氢内燃机一维模型,分别仿真分析了废气再循环(exhaust gas recirculation,EGR)技术和米勒循环技术对抑制爆震及氮氧化物(NO_(x))排放的效果,最后结合两种技术探索了可达到的最大压缩比和最好的NO_(x)排放性能。结果显示EGR技术对抑制NO_(x)排放更有效,米勒循环对抑制爆震更有效,最终在本研究的工况下,可以将内燃机的压缩比从10.0提升到18.4,指示热效率提升了8.0%,达到了44.87%,同时NO_(x)排放减少了26.2%,达到了1.937 g/(kW·h)。展开更多
文摘The EGR (exhaust gas recirculation) technique can greatly reduce the NOx emission of diesel engines, especially when an EGR cooler is employed. Numerical simulations are applied to study the flow field and temperature distributions inside the EGR cooler. Three different models of EGR cooler are investigated, among which model A is a traditional one, and models B and C are improved by adding a helical baffle in the cooling area. In models B and C the entry directions of cooling water are different, which mostly influences the flow resistance. The results show that the improved structures not only lengthen the flow path of the cooling water, but also enhance the heat exchange rate between the cool and hot media. In conclusion we suggest that the improved structures are more powerful than the traditional one.
文摘An acid-free dissolution rare-earth magnet recycling process has earned a 2018 Notable Technology Development Award from the Federal Laboratories Consortium （FLC）.
文摘建立了氢内燃机一维模型,分别仿真分析了废气再循环(exhaust gas recirculation,EGR)技术和米勒循环技术对抑制爆震及氮氧化物(NO_(x))排放的效果,最后结合两种技术探索了可达到的最大压缩比和最好的NO_(x)排放性能。结果显示EGR技术对抑制NO_(x)排放更有效,米勒循环对抑制爆震更有效,最终在本研究的工况下,可以将内燃机的压缩比从10.0提升到18.4,指示热效率提升了8.0%,达到了44.87%,同时NO_(x)排放减少了26.2%,达到了1.937 g/(kW·h)。
