Auxiliary Power Unit

Auxiliary Power Unit
Posted by Saied | Posted in Aircrafts | Posted on 02-09-2010
0
Transport aircraft
Functions of APU
APIC APS3200 APU for Airbus 318/319/320/321
The primary purpose of an aircraft APU is to provide power to start the main engines. Turbine engines have large, heavy rotors that must be accelerated to a high rotational speed in order to provide sufficient air compression for self-sustaining operation. This process takes significantly longer and requires much more energy than starting a reciprocating engine. Smaller turbine engines are usually started by an electric motor, while larger turbine engines are usually started by an air turbine motor. Whether the starter is electrically, pneumatically, or hydraulically powered, however, the amount of energy required is far greater than what could be provided by a storage device (battery or air tank) of reasonable size and weight.
An APU solves this problem by powering up the aircraft in two stages. First, the APU is started by an electric or hydraulic motor, with power supplied by a battery, accumulator, or external power source (ground power unit). After the APU accelerates to full speed, it can provide a much larger amount of power to start the aircraft’s main engines, either by turning an electrical generator or a hydraulic pump, or by providing compressed air to the air turbine of the starter motor.
APUs also have several auxiliary functions. Electrical and pneumatic power are used to run the heating, cooling, and ventilation systems prior to starting the main engines. This allows the cabin to be comfortable while the passengers are boarding without the expense, noise, and danger of running one of the aircraft’s main engines. Electrical power is also used to power up systems for preflight checks. Some APUs are also connected to a hydraulic pump, allowing maintenance and flight crews to operate the flight controls and power equipment without running the main engines. This same function is also used as a backup in flight in case of an engine failure or hydraulic pump failure.
History
A gasoline piston engine APU was first used on the Pemberton-Billing P.B.31 Nighthawk Scout aircraft in 1916. The Boeing 727 in 1963 was the first jetliner to feature a gas turbine APU, allowing it to operate at smaller, regional airports, independent from ground facilities. Although APUs have been installed in many locations on various military and commercial aircraft, they are usually mounted at the rear of modern jet airliners. The APU exhaust can be seen on most modern airliners as a small pipe exiting at the aircraft tail.
Recent designs have started to explore the use of the Wankel engine in this role. The Wankel offers power-to-weight ratios that are superior to conventional piston engines and better fuel economy than a turbine engine.
APUs fitted to ETOPS (Extended-range Twin-engine Operations) aircraft are a critical safety device, as they supply backup electricity and compressed air in place of the dead engine or failed main engine generator. While some APUs may not be startable while the aircraft is in flight, ETOPS-compliant APUs must be flight-startable at the altitudes up to the aircraft service ceiling. Recent applications have specified starting up to 43,000 ft. ( 13 000 m) from a complete cold-soak condition. If the APU or its electrical generator is not available, the airplane cannot be released for ETOPS flight and is forced to take a longer non-ETOPS route.
In case of APU failure, an air starter unit (ASU) and a ground power unit (GPU) are needed for starting the main engines on the ground and to provide electrical power to the aircraft prior to the main engine start.
Sections of APU
A typical gas turbine APU for commercial transport aircraft comprises three main sections:
Power section
Load compressor section and
Gearbox section
The power section is the gas generator portion of the engine and produces all the shaft power for the APU. The load compressor is generally a shaft-mounted compressor that provides pneumatic power for the aircraft, though some APUs extract bleed air from the power section compressor. There are two actuated devices: the inlet guide vanes that regulate airflow to the load compressor and the surge control valve that maintains stable or surge-free operation of the turbo machine. The third section of the engine is the gearbox. The gearbox transfers power from the main shaft of the engine to an oil-cooled generator for electrical power. Within the gearbox, power is also transferred to engine accessories such as the fuel control unit, the lube module and cooling fan. In addition, there is also a starter motor connected through the gear train to perform the starting function of the APU. Some APU designs use a combination starter/generator for APU starting and electrical power generation to reduce complexity.
Some APUs use an electronic control box (ECB), which is designed to control the APUs. It also serves as an interface between the subsystems of an APU and the aircraft.
With the Boeing 787 being an all electric aircraft, the APU delivers only electricity to the aircraft. The absence of a pneumatic system simplifies the design, but the demand for hundreds of kilowatts (kW) of electricity requires heavier generators and unique system requirements.
Onboard solid oxide fuel cell (SOFC) APU’s are being researched.
Manufacturers
Three main corporations compete in the aircraft APU market: Goodrich Corporation, United Technologies Corporation (through its subsidiaries Pratt & Whitney Canada and Hamilton Sundstrand), and Honeywell International Inc.
Military aircraft
Smaller military aircraft, such as fighters and attack aircraft, feature auxiliary power systems which are different from those used in transport aircraft. The functions of engine starting and providing electrical and hydraulic power are divided up among two units, the jet fuel starter and the emergency power unit.
Jet fuel starter
A jet fuel starter, or JFS, is a small turboshaft engine designed to provide power to spool the main engine up to its self-accelerating RPM. Unlike the APUs used in transport aircraft, the JFS provides power through an output shaft connected through a gearbox to the main engine, rather than through bleed air.
Unlike the APUs in transport aircraft, which are started by electrical power, a JFS is spooled up for starting by a hydraulic motor with fluid from a hydraulic accumulator (a type of pressurized fluid reservoir). The advantages of this system over an electrically started APU are extra reliability and independence from ground support. Batteries may go dead if the aircraft isn’t operated for a long period of time, while a hydraulic accumulator will stay charged indefinitely. Starting an aircraft with a JFS requires no external equipment or ground personnel, and only requires a small amount of battery power to operate the JFS controls and the electric valves in the hydraulic system. Once the main engine starts, the JFS accumulator will be almost instantly recharged by the engine-driven hydraulic pump, while a battery would take a much longer time to charge. In the event the main engine fails to start and the hydraulic accumulator is discharged, the accumulator may be recharged by a hand-operated pump onboard the aircraft.
All jet fuel starters use a free power turbine section, but the method of connecting it to the engine depends on the aircraft design. In single-engine aircraft such as the A-7 Corsair II and F-16 Fighting Falcon, the JFS power section is always connected to the main engine through the engine’s accessory gearbox. In contrast, the twin-engine F-15 Eagle features a single JFS, and the JFS power section is connected through a central gearbox which can be engaged to one engine at a time.
Emergency power unit
Emergency hydraulic and electric power are provided by a different type of gas turbine engine. Unlike most gas turbines, an emergency power unit has no gas compressor or ignitors, and uses a combination of hydrazine and water, rather than jet fuel. When the hydrazine and water mixture is released and passes across a catalyst of iridium, it spontaneously ignites, creating hot expanding gases which drive the turbine. The power created is transmitted through a gearbox to drive an electrical generator and hydraulic pump.
The hydrazine is contained in a sealed, nitrogen charged accumulator. When the system is armed, the hydrazine is released whenever the engine-driven generators go off-line, or if all engine-driven hydraulic pumps fail.
Spacecraft
APUs are even more critical for Space Shuttle flight operations. Unlike aircraft APUs, they provide hydraulic pressure, not electrical power. The Space Shuttle has three redundant APUs, powered by hydrazine fuel. They only function during powered ascent, and during re-entry and landing. During powered ascent, the APUs provide hydraulic power for gimballing of Shuttle’s engines and control surfaces. During landing, they power the control surfaces and brakes. Landing can be accomplished with only one APU working. On STS-9, two of Columbia’s APUs caught fire, but the flight still landed successfully.
Armor
APUs are also fitted to some tanks to provide electrical power when stationary, without the high fuel consumption and large infrared signature caused by running the main engine. Both the M1 Abrams and variants of the Leopard 2 such as the Spanish and Danish variants carry the APU in the rear right hull section. The British Centurion tank uses an Austin A-Series inline-4 as its auxiliary power unit.
Commercial vehicles
Diesel-powered APU on truck
The most common APU for a commercial truck is a small diesel engine with its own cooling system, heating system, generator or alternator system with or without inverter, and air conditioning compressor, housed in an enclosure and mounted to one of the frame rails of a semi-truck. Other designs fully integrate the auxiliary cooling, heating, and electrical components throughout the chassis of the truck. These units are used to provide climate control and electrical power for the truck’s sleeper cab and engine block heater during downtime on the road.
A refrigerated or frozen food semi trailer or train car may be equipped with an independent APU and fuel tank to maintain low temperatures while in transit, without the need for an external transport-supplied power source.
In the United States, federal Department of Transportation regulations require 10 hours of rest for every 11 hours of driving. During these times, truck drivers often idle their engines to provide heat, light, and power for various comfort items. Although diesel engines are very efficient when idling, it is still financially and environmentally costly to idle them like this, from a fuel consumption and an engine wear perspective. The APU is designed to eliminate these long idles. Since the generator engine is a fraction of the main engine’s displacement, it uses a fraction of the fuel; some models can run for eight hours on one US gallon ( 4 litres) of diesel. The generator also powers the main engine’s block and fuel system heaters, so the main engine can be started easily right before departure if the APU is allowed to run for a period beforehand. An APU can save up to 20 gallons (Cat 600 – 10 hours downtime @ 2 gallons per hour idling) ( 76 litres) of fuel a day, and can extend the useful life of the main engine by around 100,000 miles ( 160,000 kilometres), by reducing non-productive run time.[citation needed]
Some vehicle APUs can also use an external shore power connection for their heating and cooling functions, thus eliminating fuel consumption during rest periods altogether. Many truck stops provide shore power connections in their parking areas.
Some APUs can also use solar pv and wind power as an option for power generation that is stored in batteries for later use. Unlike other APUs renewable energy APUs use the sun and wind for power instead of a fuel to produce power to operate air conditioning and heating and other semi truck accessories. Hybrid APUs are able to replace fuel APUs.
On some older diesel engines, an APU was used instead of an electric motor to start the main engine. These were primarily used on large pieces of construction equipment.
As an alternative to the diesel units, APUs using an auxiliary battery system or hydrogen fuel cells as a source of power have also been designed. Freightliner has shown a demonstration model of a fuel cell APU, run on a tank of liquid hydrogen mounted to the truck, on one of their Century Class S/T road tractors.
Other forms of transport
Where the elimination of exhaust emissions or noise is particularly important (such as yachts, camper vans), fuel cells and photovoltaic modules are used as APUs for electricity generation.
currently the most common APU units for Highway trucks are; Wabaso, Proheat, and Espar.
Ski lifts also use an APU if the main drive (usually electric) should fail or power be lost, enabling the lift to continue to operate. They can be either gas, diesel, or propane, and are connected to the main shaft or gearbox by means of chains or belts.
See also
Wikimedia Commons has media related to: Auxiliary power units (aircraft)
Air start system
Coffman engine starter – A similar system which uses an explosive cartridge to supply gas pressure.
References
^ Pats APU
^ High-power density rotary diesel engine .. as well as Auxiliary Power Units.
^ 2004 – SOFC fuel cell APU
^ Fuel cell TRU
External links
“Armor-plated auxiliary power” design of a modern gas turbine APU
“Space Shuttle Orbiter APU”
“Sound of an APU from inside a Boeing 737 cabin”
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APU textbook

通用电气发动机集团 (GEAE)

通用电气发动机集团 (GEAE)

日期：07-01-22 01:39:33 作者：本站

一、 通用电气发动机集团 (GEAE)在中国情况简介:

GEAE是目前世界上的三大商用飞机发动机制造厂商之一，其生产的多种航空发动机可用于大型宽体飞机, 窄体飞机, 以及支线飞机。GEAE与法国斯奈克马公司合资 (50/50) 生产的CFM56系列发动机是目前最为畅销, 应用最广的发动机, 同时也是我国民用窄体飞机的主导发动机。 我国自行研制的ARJ21支线飞机也将独家采用GEAE的CF34发动机。

GEAE十分注重在新技术方面的投资和新发动机的研制。在即将问世的新一代波音B7E7梦想飞机和空客A380飞机上, GE公司均有新型研制的发动机, 以适应未来航空市场的需求。

除生产航空发动机之外, GEAE下属的GE发动机服务公司也是世界上最大的发动机维修厂家。其发动机维修车间和零部件修理车间分布于世界各地。目前共有五个GE发动机维修车间和 零部件修理车间取得了CAAC颁发的维修许可证, 并承担着中国市场上 近40% GE/CFM 发动机的维修工作。

位于厦门的GE现场支援公司是目前在中国唯一专门提供现场紧急支援的维修机构。

GEAE的航空发动机在中国一直保持着较好的安全和可靠性记录。通过与CAAC适航部门, 国内各航空公司飞行及机务部门的密切合作, GE/CFM发动机的平均装机在翼时间不断提高。 目前的最长在翼无换发时间已接近三万小时。 国航, 云航, 海航, 深航, 新疆航均收到过GE/CFM公司对发动机使用方面的表彰。

2004年初, 通用电气发动机集团 (GEAE) 与 原通用电气运输集团 (生产火车车头) 合并, 改称为 “通用电气交通运输集团” (GE Transportation)。 原发动机集团总裁Mr. Dave Calhoun 现任通用电气交通运输集团总裁。


二、 GEAE与CAAC及各航空公司的合作:

· 与CAAC, 航材公司, 飞行学院, 和法国斯奈克马公司在广汉合资组建机务培训学校, 到目前共培训中国民航机务人员400多人次。


· 与航材公司在北京合资成立航材寄售仓库, 为航空公司提供了便捷的服务, 同时也降低了航空公司因航材储备而造成的资金积压。

· 为各航空公司提供管理培训和六个西格码培训, 特别是为东航和海航提供了较大范围的管理人员培训和六个西格码培训。

· 每年为各航空公司提供高层管理人员培训和财务主管人员培训。 并每年定期举办航空维修技术研讨会。

· 开展 “立足于客户, 服务于客户” 活动, 为东航, 上航, 海航, 国航, 南航, 和AVIC I提供六个西格码黑带培训并通过实施六个西格码项目, 帮助航空公司降低成本, 提高管理水平。

· 积极参与ARJ21支线飞机项目, 并在国内, 国外努力推广介绍ARJ21飞机。积极帮助AVIC I集团的飞机取证工作, 协调CAAC与美国FAA的沟通交流活动。

· 努力扩大航空产品在中国的采购量。 在过去的三年中, 年采购量年年翻番。


附1: GE主要发动机产品及中国用户

· GE90 (B777)—中国南方航空公司
· CF6 (A300-600, B767)—中国东方西北航空公司, 中国国际航空公司
· CFM56-5C (A340-300)—中国国际航空公司, 中国东方航空公司
· CFM56-5B (A320系列)—国航, 南航, 东航
· CFM56-7 (B737新一代)—国航, 南航, 东航, 海航, 深航, 厦航, 上航, 山航, 联航
· CFM56-3 (B737)--国航, 南航, 东航, 海航, 深航, 厦航, 上航, 山航, 联航
· CF34 (支线飞机)—东航, 山航, 上航, 联航

总装机数量 (截至2004年3月):
· 宽体机(WB): 35架
· 窄体机(NB & RJ): 371架

美国霍尼韦尔公司简介

美国霍尼韦尔公司简介

日期：07-01-22 01:35:57 作者：本站

霍尼韦尔公司是一家销售额为256亿美元，在多元化技术和制造业方面占世界领先地位的公司。在全球，我们的业务涉及航空航天产品及服务、自动化 控制、特殊材料以及交通系统等领域。霍尼韦尔公司在全球近100个国家拥有10.8万名员工，总部设在美国新泽西州MORRISTOWN。在纽约、伦敦、 芝加哥证交所和太平洋证交所上市交易。为道琼斯工业指数的30家成分股公司之一，也是“标准普尔500指数”的组成部分。公司资料详情备索：www.honeywell.com 。





航空航天集团

起飞在中国



与客户长期的密切合作关系和前沿的技术使霍尼韦尔航空航天集团成为向商用飞机、支线飞机、通用飞机和军用飞机提供航空发动机、设备、系统和服务的第一大供应商。



霍尼韦尔航空航天集团分别由三个业务单元和两个市场部分组成；他们分别是航空电子系统；飞机着陆系统；航空发动机、附件系统及售后服务三个业务单元；市场分为商用市场和空间防御市场两个部分。



霍尼韦尔航空航天集团除了生产和制造飞机辅助动力装置、轮船和陆地增压动力系统、商用航空电子设备、发动机和管理系统、飞机内外照明系统等多种产品外；还提供飞机检修和修理服务；备件、消耗性硬件供应和库存支援服务；空间和通讯设备的管理和技术服务。



在中国，霍尼韦尔航空航天工业集团已经成立了四家航空业界领先的合资企业，为中国境内外的客户提供机轮和刹车检修和修理、飞机环境控制系统、发动机配件和保养服务等。



业务介绍



上海东联航空机轮刹车大修工程有限公司

上海东联航空机轮刹车大修工程有限公司由中国东方航空公司和霍尼韦尔国际财务公司合资创立，专业从事各种机型的机 轮、刹车、相关零部件的维护、修理和检修业务，同时提供碳刹车片修复业务。公司成立至今，已授权为来自20余家航空公司的20余种机型提供维修服务。上海 东联航空机轮刹车大修工程有限公司已获得美国联邦航空局和中国民用航空总局的维修许可证, 并已获得ISO9002国际质量体系认证。



凯信航空附件（南京）有限公司

凯信航空附件（南京）有限公司由霍尼韦尔公司和中国航空附件研究所共同投资兴办。面向国内、外市场，设计、开发、生 产和销售商用飞机的环境控制系统，并且生产出口的飞机零配件，其中包括波音737热交换器镍基合金法兰、镍基合金压力传感器接头和波音737、757飞机 环控系统管道及小管道铝组件。



凯联航空发动机(苏州)有限公司

凯联航空发动机(苏州)有限公司由霍尼韦尔发动机系统公司与中国航空技术进出口总公司合资成立。成立初始，该公司主 要生产面向全球市场的各种发动机、辅助发动机的零部件，产品全部反销回美国。如今，该公司计划开发飞机发动机的生产模型并进行生产可行性分析和测试，最终 将该厂生产的小型涡沦发动机将投放到亚洲市场。

The ultimate goal of Honeywell CATIC is to become the small gas turbine manufacturer in Asia.



霍尼韦尔太古（厦门）宇航有限公司

霍尼韦尔太古（厦门）宇航有限公司(HTAC)成立于1995年12月，是霍尼韦尔公司的一家合资企业。主要为中国 各航空公司和途径中国的北亚地区的航空公司提供GTCP85 和GTCP331系列民用飞机辅助动力发动机、辅助动力发动机附件、纽姆阀门、飞机自动实验系统、中央显示器/协议数据单元、热交换器，HMU和航空电子 设备零部件的维修、地面保养及相关服务业务。霍尼韦尔太古宇航（厦门）有限公司已获得中国民用航空总局适航司(CAAC)、美国联邦航空局(FAA)及香 港民航处适航部(CAD)颁发的大修/维修许可证。作为DNV-ISO9002的认证企业，霍尼韦尔太古宇航（厦门）有限公司尽量达到客户的最大满意度， 为客户提供高质量、周期短和最大价值的服务

131-9B

737NG飞机的APU系统型号：

功能：提供电源和气源给飞机的使用系统。

 10000英尺以下，可同时提供电90KVA和气源； 10000－17000英尺，可供电90KVA或气源；
17000－32000英尺  ，只能供电90KVA；32000－41000英尺，只能供电66KVA；

 该APU长144cm,宽87vm,高75cm,净重177KG.

正常转速：100%转速为48800rpm,超速转速：106%，51728RPM

APU系统共包括9个子系统分别是:

1* APU power plant (49-10)
2* APU engine (49-20)
3* APU fuel system (49-30)
4* APU ignition and start system (49-40)
5* APU bleed air system (49-50)
6* APU controls (49-60)
7* APU indicating system (49-70)
8* APU exhaust system (49-80)
9* APU lubrication system (49-90).

这种APU是单轴恒速传动装置，动力部分采用单级离心式压气机，有一个

反流环形燃烧室和两级涡轮。在APU的启动系统中有SPU和SCU用来控制APU

的启动，功能是将交直流转换。

APU的控制中心就是ECU，电子控制组件，位于后货舱的右侧，功能是与飞机

其他系统进行接口。在电子设备舱中还有一个AGCU，APU发电机控制组件。