En­gine man­u­fac­tur­ers are in­vest­ing heav­ily in al­ter­na­tive fu­els and lead­ing-edge tech­nolo­gies such as ad­di­tive man­u­fac­tur­ing and nano­ma­te­ri­als to make even greener and qui­eter en­gines

SP's Airbuz - - Table of Contents - BY R. CHAN­DRAKANTH

THE IN­TER­NA­TIONAL CIVIL AVI­A­TION Or­gan­i­sa­tion (ICAO) has warned that the avi­a­tion in­dus­try needs to pre­pare for se­vere dis­rup­tions as a re­sult of cli­mate change and that it needs to make full use of clean tech­nol­ogy and pol­icy tools in or­der to re­duce its car­bon foot­print. ICAO’s 2016 En­vi­ron­men­tal Re­port says that changes to the at­mos­phere brought about by ris­ing global tem­per­a­tures caused by green­house gas emis­sions, will af­fect air­plane’s abil­ity to fly, while ris­ing sea lev­els will af­fect air­ports. Im­pacts will in­clude higher winds im­ped­ing the abil­ity of air­craft to take­off and an in­crease in-flight tur­bu­lence, ic­ing and en­gine-threat­en­ing dust storms. With such en­vi­ron­men­tal con­cerns, there are var­i­ous or­gan­i­sa­tions across con­ti­nents work­ing on sus­tain­able al­ter­na­tives.

The Air Trans­port Ac­tion Group (ATAG), a not-for-profit as­so­ci­a­tion, has stated that world­wide, flights pro­duced 781 mil­lion tonnes of CO in 2015, while over all hu­mans pro­duced 36 bil­lion tonnes. The global avi­a­tion in­dus­try pro­duces around two per cent of all hu­man-in­duced CO emis­sions. Avi­a­tion is re­spon­si­ble for 12 per cent of CO emis­sions from all trans­port sources com­pared to 74 per cent from road trans­port. Around 80 per cent of avi­a­tion CO emis­sions are from flights of over 1,500 km for which there is no prac­ti­cal al­ter­na­tive mode of trans­port. RE­DUC­TIONS IN FUEL BURN. The Sus­tain­able and Green En­gine (SAGE) ITD of Clean Sky demon­strates five en­gine tech­nolo­gies con­tribut­ing to­wards the Ad­vi­sory Coun­cil for Aero­nau­tic Re­search in Europe (ACARE) en­vi­ron­men­tal tar­gets. There are six en­gine projects con­tained in the pro­gramme. Each one tar­gets spe­cific tech­nolo­gies and mar­ket sec­tors, led by a member of the Euro­pean en­gines in­dus­try.

Open ro­tor tech­nolo­gies of­fer the po­ten­tial for sig­nif­i­cant re­duc­tion in fuel burn and CO emis­sions rel­a­tive to tur­bo­fan en­gines of equiv­a­lent thrust. Higher propul­sive ef­fi­cien­cies are achieved for tur­bo­fans by in­creas­ing the by­pass ra­tio through in­crease in fan di­am­e­ter, but there is a di­min­ish­ing re­turn to this im­prove­ment as na­celle di­am­e­ters and con­se­quently weight and drag in­crease. Open ro­tor en­gines re­move this lim­i­ta­tion by op­er­at­ing the pro­pel­ler blades with­out a sur­round­ing na­celle, thus en­abling ul­tra­high by­pass ra­tios to be achieved.

Fur­ther im­prove­ments in propul­sive ef­fi­ciency can be gained in open ro­tor en­gines by us­ing a sec­ond row of pro­pel­ler blades ro­tat­ing in op­po­site di­rec­tion to the front row to re­move the spin from the col­umn of air to give a more di­rect thrust. The tech­ni­cal chal­lenges of counter-ro­tat­ing open ro­tor en­gines are many, but are prin­ci­pally re­duc­tion of the noise cre­ated by the pro­pel­ler blades to counter the loss of at­ten­u­a­tion pro­vided by a tur­bo­fan na­celle. OPEN RO­TOR EN­GINE. Tur­bo­fans are iso­lated from the air­frame by the na­celle, but the air­flow through open ro­tor pro­pel­lers in­ter­acts with the sup­port­ing air­frame struc­ture and so the in­stal­la­tion im­pacts on the en­gine sys­tem noise and ef­fi­ciency.

Rolls-Royce has de­vel­oped open ro­tor pro­pel­ler de­sign to min­imise noise and has demon­strated the ef­fec­tive­ness of these de­signs through scaled rig test­ing in the FP7 DREAM pro­gramme. The SAGE1 project is planned to ac­quire tech­nol­ogy for the propul­sion sys­tem, in­creas­ing the Tech­nol­ogy Readi­ness Level (TRL) to TRL 5. Col­lab­o­rat­ing in the SAGE1 project un­der Rolls-Royce lead­er­ship are Volvo Aero Cor­po­ra­tion and ITP. Fur­ther Part­ners will be se­lected as the project pro­gresses. LARGE 3 SHAFT DEMON­STRA­TOR. The SAGE3 project is fo­cused on low pres­sure sys­tem and ex­ter­nal tech­nolo­gies. Rolls-Royce has been devel­op­ing com­pos­ite fan tech­nolo­gies in the Frame­work Pro­gramme 6 (FP6) VI­TAL and ELF pro­grammes, but the tech­nol­ogy re­quires en­gine demon­stra­tion to achieve Tech­nol­ogy Readi­ness Level 6, the en­vi­ron­ment in which it will op­er­ate. The SAGE3 project will in­clude an en­gine demon­stra­tion (the Ad­vanced Low Pres­sure Sys­tem, or ALPS, demon­stra­tor) to pro­vide this ver­i­fi­ca­tion.

Fur­ther tech­nol­ogy demon­stra­tion in the SAGE3 project will fo­cus on ad­vanced ex­ter­nals, with en­gine demon­stra­tion op­por­tu­ni­ties of­fered to ad­vanced sys­tems to re­duce the weight of the in­stal­la­tions. These lightweight in­te­grated sub-sys­tems will fo­cus on util­i­sa­tion of com­pos­ite and other lightweight ma­te­ri­als, on im­proved in­te­gra­tion of ex­ter­nals with the en­gine struc­ture and ex­ten­sion of ex­ist­ing lightweight so­lu­tions to higher tem­per­a­ture ap­pli­ca­tions. Low pres­sure tur­bine tech­nolo­gies will be de­vel­oped and demon­strated by ITP and com­pres­sor in­ter­case tech­nolo­gies by Volvo Aero.

The ba­sis for the en­gine demon­stra­tion will be a Trent 1000 en­gine and planned test­ing in­cludes a full range of aero­dy­namic and noise tests on in­door and out­door test stands and in flight. Rig test­ing is planned for com­po­nents where ei­ther this will pro­vide full val­i­da­tion such as for the in­ter­case tech­nolo­gies or where a lim­ited en­gine dataset will ver­ify the re­sults of a more com­plete rig test sur­vey. Col­lab­o­rat­ing in the SAGE3 project un­der Roll­sRoyce lead­er­ship are Volvo Aero Cor­po­ra­tion, ITP, FACC and Univer­sity of Rap­per­swil. LEAN BURN DEMON­STRA­TOR. The SAGE6 project is fo­cused on de­liv­er­ing a lean burn com­bus­tion sys­tem demon­stra­tor en­gine. The aim is to demon­strate a lean burn whole en­gine sys­tem to a TRL6 ma­tu­rity level, suit­able for in­cor­po­ra­tion into civil aerospace ap­pli­ca­tions in the 30,000lb to 100,000 plus thrust classes. SAGE6 is con­tin­u­ing on from pre­vi­ous demon­stra­tor pro­grammes such as ANTLE/POA, E3E and EFE. The SAGE6 project will in­clude an en­gine demon­stra­tion (Ad­vanced Low Emis­sion Com­bus­tion, or ALECSYS demon­stra­tor) to pro­vide this ver­i­fi­ca­tion.

Fur­ther tech­nol­ogy demon­stra­tion in the SAGE6 project will fo­cus on lean burn com­bus­tion tech­nol­ogy, ad­vanced en­gine health mon­i­tor­ing, ad­vanced cool­ing tech­nolo­gies, ad­vanced fuel heat man­age­ment and im­proved man­u­fac­tur­ing ca­pa­bil­i­ties. Cur­rent TRL lev­els of the var­i­ous sub­sys­tems vary, but are typ­i­cally at TRL3-4. Whilst ex­ist­ing demon­stra­tor plat­forms (rigs and en­gines) will be suf­fi­cient to develop the sys­tem to TRL5, ad­di­tional ca­pa­bil­ity in the form of a ground demon­stra­tor will be re­quired. This ve­hi­cle will en­com­pass the en­tire lean burn sys­tem in­clud­ing the com­bus­tor, fuel sup­ply and con­trol sys­tem, sens­ing tech­nolo­gies and the as­so­ci­ated ex­ter­nals and in­stal­la­tion hard­ware and rep­re­sents a sig­nif­i­cant set of mod­i­fi­ca­tions to the ar­chi­tec­ture of the Trent 1000 donor en­gine. Col­lab­o­ra­tion in the SAGE6 project un­der Rolls-Royce lead­er­ship is through part­ners se­lected through the Clean Sky Call for Pro­posal process as the project pro­gresses. PUREPOWER AND QUI­ETER AIR­PORTS. Pratt & Whit­ney’s new PurePower Geared Tur­bo­fan (GTF) en­gine is an­other en­gine that is de­signed to ad­dress en­vi­ron­men­tal con­cerns. The en­gine re­duces its noise foot­print by 75 per cent, while also de­liv­er­ing a 16 per cent im­prove­ment in fuel ef­fi­ciency and re­duc­ing NOx emis­sions by 50 per cent to the reg­u­la­tory limit.

Pratt & Whit­ney states “If ev­ery air­plane de­part­ing LaGuardia was pow­ered by a Geared Tur­bo­fan en­gine, about 500,000 few air­port neigh­bours would be im­pacted by noise from take­off and land­ing.” This en­gine not only leads to qui­eter neigh­bor­hoods near air­ports – it’s a key to the health of fu­ture cities and skies, too. As our population grows and ur­banises and with air travel ex­pected to double by 2035, we will need a way to not only con­nect ur­ban cen­tres, but also pro­tect the planet. One way to do that is through green avi­a­tion tech­nol­ogy like the Geared Tur­bo­fan en­gine.”

Pratt & Whit­ney and its par­ent com­pany, For­tune 45 man­u­fac­turer United Tech­nolo­gies Cor­po­ra­tion, are in­vest­ing heav­ily in al­ter­na­tive fu­els and lead­ing-edge tech­nolo­gies such ad­di­tive man­u­fac­tur­ing and nano­ma­te­ri­als to make even greener, qui­eter en­gines. LEAP’S REV­O­LU­TION­ARY TECH­NOL­OGY. Sim­i­larly, the next-gen­er­a­tion LEAP en­gine of­fered by CFM In­ter­na­tional (a 50/50 com­pany be­tween Safran Air­craft En­gines and GE), fea­tures a rev­o­lu­tion­ary new tech­nol­ogy. The fan blades and cases on this en­gine are made of a 3D wo­ven com­pos­ite us­ing the Resin Trans­fer Mold­ing (RTM) process, to suf­fi­ciently de­crease en­gine weight, which in turn re­duces fuel con­sump­tion and NOx (ox­ides of ni­tro­gen) emis­sions.


PW1000G PurePower en­gine

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