VALVE BLEED HP高压引气活门(HPV)是发动机内引气系统的HP / IP气动输送系统的一个部件。HPV调节向飞机空调系统和机翼防冰系统提供的空气压力。HPV在飞机上的显示故障信息大多数为:HF BLEED-V 4000HA1 OR SENSE LINE,HF BLEED-V 4000HA...VALVE BLEED HP高压引气活门(HPV)是发动机内引气系统的HP / IP气动输送系统的一个部件。HPV调节向飞机空调系统和机翼防冰系统提供的空气压力。HPV在飞机上的显示故障信息大多数为:HF BLEED-V 4000HA1 OR SENSE LINE,HF BLEED-V 4000HA2 OR SENSE LINE,二发高压活门故障,左阀高压引气活门未关闭,航后检查左发HPV活门显示在开位等。这些信息便于航线人员从整机的系统进行判断,但对于实际的航空附件维修过程中,这些航线显示信息只能说明HPV出现故障,需要从飞机上拆换,但并不能针对性说明HPV具体的故障信息。因此仍需要对单机件进行测试,排故等一系列的操作程序来确定基体出现故障的原因,然后才是修理、更换、验收测试等。经过对HPV维修的历史的数据统计分析和对机件结构原理进行分析后,总结出常见的故障现象和处理措施。以节约排故的时间和降低高温反复调试和测试的成本。展开更多
Research on dual-fuel(DF)engines has become increasingly important as engine manufacturers seek to reduce carbon dioxide emissions.There are significant advantages of using diesel pilot-ignited natural gas engines as ...Research on dual-fuel(DF)engines has become increasingly important as engine manufacturers seek to reduce carbon dioxide emissions.There are significant advantages of using diesel pilot-ignited natural gas engines as DF engines.However,different combustion modes exist due to variations in the formation of the mixture.This research used a simulation model and numerical simulations to explore the combustion characteristics of high-pressure direct injection(HPDI),partially premixed compression ignition(PPCI),and double pilot injection premixed compression ignition(DPPCI)combustion modes under a low-medium load.The results revealed that the DPPCI combustion mode provides higher gross indicated thermal efficiency and more acceptable total hydrocarbon(THC)emission levels than the other modes.Due to its relatively good performance,an experimental study was conducted on the DPPCI mode engine to evaluate the impact of the diesel dual-injection strategy on the combustion process.In the DPPCI mode,a delay in the second pilot ignition injection time increased THC emissions(a maximum value of 4.27g/(kW·h)),decreased the emission of nitrogen oxides(a maximum value of 7.64 g/(kW·h)),increased and then subsequently decreased the gross indicated thermal efficiency values,which reached 50.4%under low-medium loads.展开更多
文摘VALVE BLEED HP高压引气活门(HPV)是发动机内引气系统的HP / IP气动输送系统的一个部件。HPV调节向飞机空调系统和机翼防冰系统提供的空气压力。HPV在飞机上的显示故障信息大多数为:HF BLEED-V 4000HA1 OR SENSE LINE,HF BLEED-V 4000HA2 OR SENSE LINE,二发高压活门故障,左阀高压引气活门未关闭,航后检查左发HPV活门显示在开位等。这些信息便于航线人员从整机的系统进行判断,但对于实际的航空附件维修过程中,这些航线显示信息只能说明HPV出现故障,需要从飞机上拆换,但并不能针对性说明HPV具体的故障信息。因此仍需要对单机件进行测试,排故等一系列的操作程序来确定基体出现故障的原因,然后才是修理、更换、验收测试等。经过对HPV维修的历史的数据统计分析和对机件结构原理进行分析后,总结出常见的故障现象和处理措施。以节约排故的时间和降低高温反复调试和测试的成本。
基金Project(2017YFE0102800)supported by the National Key R&D Program of ChinaProject(19JCYBJC21200)supported by the Tianjin Natural Science Foundation,China。
文摘Research on dual-fuel(DF)engines has become increasingly important as engine manufacturers seek to reduce carbon dioxide emissions.There are significant advantages of using diesel pilot-ignited natural gas engines as DF engines.However,different combustion modes exist due to variations in the formation of the mixture.This research used a simulation model and numerical simulations to explore the combustion characteristics of high-pressure direct injection(HPDI),partially premixed compression ignition(PPCI),and double pilot injection premixed compression ignition(DPPCI)combustion modes under a low-medium load.The results revealed that the DPPCI combustion mode provides higher gross indicated thermal efficiency and more acceptable total hydrocarbon(THC)emission levels than the other modes.Due to its relatively good performance,an experimental study was conducted on the DPPCI mode engine to evaluate the impact of the diesel dual-injection strategy on the combustion process.In the DPPCI mode,a delay in the second pilot ignition injection time increased THC emissions(a maximum value of 4.27g/(kW·h)),decreased the emission of nitrogen oxides(a maximum value of 7.64 g/(kW·h)),increased and then subsequently decreased the gross indicated thermal efficiency values,which reached 50.4%under low-medium loads.
