增压与空调系统.ppt

Air Condition System And Pressurization System Air Condition System 以B747-800为例 747-8 engine bleed system 747-8 engine bleed system The 747-8 airplane is powered by General Electric GENX-2B engines. The engine bleed systems supply air from the engine compressor. There are four identical engine bleed systems per airplane with independent control and indication for each system 747-8 engine bleed system The system schematic (top) and component locations (bottom) in the 747-8 engine bleed system. 747-8 engine bleed system The air temperature and air pressure are regulated before being delivered to airplane systems. The bleed air is used for CACTCS, engine anti-ice, wing anti-ice, the hydraulic air-driven pump, the leading-edge flap drive unit, the nitrogen generation system, aft cargo heat, total air temperature probe aspiration, and hydraulic reservoir pressurization. All four engine bleed systems are connected by a common manifold. 747-8 engine bleed system Technological advancements enabled Boeing to make several improvements to the bleed system on the 747-8. These improvements include: 747-8 engine bleed system New digital bleed The system has no mechanical position switches and reduced use and consolidation of sensors. 747-8 engine bleed system No remote valve controllers The torque motor and solenoid are built into the valve design, allowing for easier troubleshooting and improved fault isolation. 747-8 engine bleed system Fewer servo/sense lines This increases system reliability. 747-8 SUBFREEZING PACK 747-8 SUBFREEZING PACK The 747-8 air-conditioning pack has several key features that allow it to be classified as a true subfreezing pack, which will operate to temperatures below the freezing point of water at all altitudes (see fig. 747-400 air-conditioning pack system). 747-8 SUBFREEZING PACK While earlier air-conditioning packs can drive subfreezing during all conditions, there are limitations that need to be placed upon the system due to the oper