| Pratt & Whitney PW1000G | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 送交者: 2018年02月12日04:12:50 于 [世界军事论坛] 发送悄悄话 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Pratt & Whitney PW1000GFrom Wikipedia, the free encyclopedia
The Pratt & Whitney PW1000G is a high-bypass geared turbofan engine family, currently selected as the exclusive engine for the Bombardier CSeries, Mitsubishi Regional Jet (MRJ), and Embraer's second generation E-Jets, and as an option on the Irkut MC-21 and Airbus A320neo. The project was previously known as the Geared Turbofan (GTF), and originally the Advanced Technology Fan Integrator (ATFI). The engine is expected to deliver reductions in fuel use and ground noise when used in next-generation aircraft. The PW1000G engine first entered commercial use in January 2016 with Lufthansa's first commercial Airbus A320neo flight.[3] Contents[hide] Development[edit]
Pratt & Whitney first attempted to build a geared turbofan starting around 1998, with the PW8000.[4] This essentially was an upgrade of the existing PW6000that replaced the fan section with a gearing system and new single-stage fan.[5] After several years of development the PW8000 essentially disappeared.[6] Soon afterwards the ATFI project appeared, using a PW308 core but with a new gearbox and a single-stage fan. It had its first run on March 16, 2001. This led to the Geared Turbofan (GTF) program, which was based around a newly designed core jointly developed with German MTU Aero Engines. In addition to the geared turbofan, the initial designs included a variable-area fan nozzle (VAFN), which allows improvements in propulsive efficiency across a range of the flight envelope.[7] However, the VAFN has since been dropped from production designs due to high system weight. In July 2008, the GTF was renamed PW1000G, the first in a new line of "PurePower" engines.[8] Pratt & Whitney claims the PW1000G is 16% more fuel efficient than current engines used on regional jets and single-aisle jets, as well as being up to 75% quieter.[9] Flight testing[edit]
The engine was first tested on the Pratt & Whitney Boeing 747SP, then since October 14, 2008 on an Airbus A340-600 in Toulouse on the number two pylon.[10] Testing of the CSeries bound PW1524G model began in October 2010.[11] The PW1500G engine successfully achieved Transport Canada type certification on February 20, 2013.[12] The A320 engine, the PW1100G, was first tested on the 747SP on 15 May 2013.[13] The first flight test on one of its intended production airframes, the Bombardier CS100, was on September 16, 2013.[14] The first flight of the Airbus A320neo followed on September 25, 2014.[15] The PW1100G engine successfully achieved FAA type certification on December 19, 2014.[16] The fourth variant of the engine, the PW1900G, first flew on November 3, 2015 from Mirabel in Canada fitted to the Boeing 747SP test aircraft.[17] Production[edit]
At the start of its production in 2016, each GTF was costing PW $10m to build, more than the sale price, but should become less than $2m per engine.[18] MTU provides the first four stages of the high-pressure compressor, the low-pressure turbine and other components. In October 2016, MTU started to deliver the engine assembled on its line to Airbus.[19] In November 2016, Pratt had fixed the issue of engine start time and wanted to deliver 150 powerplants by the year-end, 50 fewer than originally planned. This was because of low yield of Fan Blades when less than one-third were passing inspection at the start of the year compared to 75% success for the latest. 350–400 engine deliveries are targeted for 2017. Fuel-burn performance is 16% better than the IAE V2500 baseline, on target, and even 18% better in best cases.[20] The troubled introduction is making customers choose the CFM LEAP which won 396 plane orders compared to 39 from January through early August 2017 to power the A320neo: 46% of the GTF-powered A320neos were out of service for at least one week in July 2017 compared with just 9% of those using the LEAP, while its market share fell from 45% to 40% in 2016 but 1,523 planes (29%) are still undecided and Pratt have a 8,000 engine orderbook including 1,000 non-Airbus planes.[21] On 24 October 2017, a 99.8% dispatch reliability is attained and Pratt remains on track to deliver 350 to 400 engines in 2017, as 254 have been delivered including 120 in the third quarter, but 12–15% are diverted for spares as the carbon air seal and combustor liners are wearing out fast, requiring engine removals to change the part.[22] Ultra high-bypass version[edit]In 2010, Pratt & Whitney launched the development of an ultra high-bypass version, with a ratio significantly higher than the PW1100G's 12.2:1 for the A320neo, to improve fuel consumption by 20% compared to a CFM56-7 and reduce noise relative to the FAA’s Stage 4 by 25dB. In 2012, wind tunnel tests were completed on an earlier version of the fan and in 2015, 275h of testing were completed on a fan rig. More than 175h of ground testing of key components were completed in October 2017, on a shorter duct inlet, a part of the nacelle and a fan with lower-pressure ratio blades, significantly fewer than the 20 blades of the PW1100G. The US FAA Continuous Lower Energy, Emissions and Noise (CLEEN) program sponsors the tests, with is technologies to be validated in a flight test campaign. It could power the Boeing New Midsize Airplane in the mid-2020s and Airbus' response, and would compete against the Rolls-Royce UltraFan and a CFM LEAP higher-thrust version.[23] Design[edit]By putting a 3:1 gearbox between the fan and the low-pressure spool, each spins at its optimal speed: 4,000–5,000 RPM for the fan and 12,000–15,000 RPM for the spool, the high-pressure spool spinning at more than 20,000 RPM. The 30,000 hp gearbox is designed as a lifetime item with no scheduled maintenance other than changing oil.[24] The A320 PW1100G fan has 20 blades, down from 36 in the CFM56-5B.[25] As the higher bypass ratio and gear leverage a higher propulsive efficiency, there is less need for a high performance engine core than the CFM LEAP, leaving a larger fuel burn gain margin of 5–7% over the next decade, averaging 1% per year combined with gear ratio tweaks.[26] Operational history[edit]Introduction[edit]
The first delivery to a commercial operator, an A320neo to Lufthansa, occurred on January 20, 2016.[27] As of early August 2017, Pratt was supporting 75 aircraft: 59 Airbus A320neos with PW1100Gs and 16 Bombardier C Series with PW1500Gs.[28] In January 2018, it reached 500,000 flight hours on a fleet of 135 aircraft flown by 21 operators.[29] Starting times[edit]The first delivery was to Lufthansa instead of Qatar Airways due to rotor bow, or thermal bowing, due to asymmetrical cooling after shut-down on the previous flight. Differences in temperature across the shaft section supporting the rotor lead to different thermal deformation of the shaft material, causing the rotor axis to bend; this results in an offset between the center of gravity of the bowed rotor and the bearing axis, causing a slight imbalance and potentially reducing the tight clearance between the rotor blade tips and the compressor wall. All production standard engines now feature a damper on the third and fourth shaft bearings to help stiffen the shaft and data from engines in service and under accelerated testing is expected to gradually reduce engine start times. According to P&W President Bob Leduc, "by the time we get to June (2016), it will be down to 200 seconds for start time and by the time we get to December (2016) we will be down to 150 seconds for start time".[30] In an earnings briefing on 26th July the CEO of Pratt & Whitney's parent company United Technologies Gregory Hayes stated when asked about the start up issues on the PW1100G-JM; "On the technical stuff, I would tell you it is in the rearview mirror. The start time with the software drops have been pretty well addressed".[31] Airbus group chief Tom Enders said while releasing Airbus's 2016 first half financial results that the first upgraded "golden engine" would be delivered to Lufthansa in early August 2016.[32] Initially, the PW1000G start up sequence took about seven minutes, compared to one to two and a half minute startups on the similar CFM56 and IAE V2500 engines; hardware fixes and software upgrades decreased the time required by a little over a minute, and cooling down both engines at the same time saved slightly over two minutes, for a total reduction of three and a half minutes. These modifications were included on new-build engines, as well as retrofitting existing units. Pratt & Whitney continued to improve start up times, with fuel-nozzle modifications and oil filling procedure changes expected to save another minute when introduced by the end of 2017.[33] To create a better seal and reduce cooling time by 1 min, a cubic boron nitride coating was applied to the 11 integrally bladed rotors tips: the A321neo production engines start times will be similar to the V2500.[34] Engine removals[edit]
As IndiGo and Go Air operate in humid, hot, polluted and salty environment, 42 engines were prematurely removed from those companies' aircraft by 24 February, with more to come and after certain warnings mandatory checks and possible repairs are due after only three flight hours instead of ten : 28 engine removals were due to an air seal leakage in the third bearing, allowing metal particles to enter the oil system, triggering detectors. Pratt & Whitney discovered these issues in 2015 and revised the design in 2016 after the 160th engine with improved bearing compartments and damping for the third and fourth bearings to offset the rotor-bow, with the repairs retrofitted on-wing after testing at Airbus and Pratt.[33] Boosting durability of the third bearing compartment air seal, the upgraded carbon seal package was certified on April 12 and can be retrofited over a typical night stop.[35] Thirteen engine removals were due to borescope inspections revealing blocked cooling holes in combustion chamber panels, apparently due to saltier air, and Pratt & Whitney developed and tested a more durable combustor design to address a tone problem, with the fix to be introduced in September.[33] Spirit Airlines reported that the bleed air system froze shut on occasion due to cold temperatures on four of its five A320neos, a problem also experienced by IndiGo, leading Spirit to impose a 30,000 feet (9,100 m) ceiling on their aircraft.[36] As Pratt troubles persists, JetBlue Airways has switched its first three Airbus A321neos in 2018 to A321ceos and will now take delivery of its first A321neos in 2019 among its order for 60.[37] In 2017, IndiGo had to ground seven planes, two in May, four in June and one in July after, their engines out of service, waiting for upgrades: a lack of spare parts—grounding also All Nippon Airways and Hong Kong Express Airways A320s—has been compounded by a new Indian tax on goods and services impeding imports.[38] With removals without sufficient spare engines available, the airline had to ground as many nine jets on some days, operations disruptions are understood by Pratt & Whitney which struggles to fix glitches and sent compensation while design changes could take a year and sorting out the issue one and a half years.[39] Groundings[edit]In February 2018, after in-flight failures of PW1100G with its high pressure compressor aft hub modified – apparently problems of its knife edge seal, the EASA and Airbus grounded some A320neo familyaircraft until they are fitted with spares.[40] Later, Airbus decided to stop accepting additional PW1100G engines for A320neo aircraft.[41] Applications[edit]
It has been proposed for the Sukhoi Superjet 130,[50] and the Rekkof Aircraft F-120NG (nl).[51] Specifications[edit]
See also[edit]
Notes[edit]
References[edit]
External links[edit]
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
.jpg)
.jpg)
|
|
 |
 |
| 实用资讯 | |
|
|
|
|
| 一周点击热帖 | 更多>> |
|
|
|
| 一周回复热帖 |
|
|
| 历史上的今天：回复热帖 |
| 2017: | 川普他一个生意人不懂的治国 | |
| 2017: | Zt 评老兵 zhihu | |
| 2016: | BBC:“令完成否认向美国交出中国国家机 | |
| 2016: | 六座岛礁的守卫兵力就这样泄露了 zt | |
| 2015: | 中俄宽体机项目效果图 | |
| 2015: | 人工智能会最终毁灭人类? 大部分中国专 | |
| 2014: | 强烈推荐：张维为：中国崛起与文明型国 | |
| 2014: | 中国为何铁了心买苏35：看完这个你就全 | |
| 2013: | 中央急调大军到中朝边境 朝鲜核爆最大赢 | |
| 2013: | 中国测得朝鲜发生有感地震 似乎核试 美 | |
|
|