Intéressant et à lire !
L'évolution, assez compliquée des TXWB pour aller chercher les 97 000 lbs !
Selon AvWeek; par Guy Norris !http://www.aviationweek.com/Article.aspx?id=/article-xml/avd_02_12_2013_p01-01-547721.xml
J'édite, pour en garder la trace , c'est intéressant de suivre l'impressionnante gymnastique à laquelle se livre RR pour rester dans la boite !
Coûteux, mais certainement efficace, pour ne pas grimper en conso !
80% de pièces communes, et on peu penser qu'une part pourra re-descendre un jour !
Bien, on a vu aussi que les très hautes compressions, ne sont pas gratuites, côté poids !
------------- Extrait de AvWeek, Guy Norris ------------
R-R in January completed the preliminary design review (PDR) for the
97,000-lb.-thrust-rated Trent XWB-97. “This is a key milestone for us,
as it takes us into detailed design and the making of individual
components of engines, the pouring of castings and the creating of
forgings. It also enables us to get ready to begin machining,” says
Young. Although the XWB-97 is sized for considerably greater thrust,
Young says a success from the PDR will be confirmation that 80% of the
line-replaceable units will be common
for the various engine variants.
The only exceptions will be fuel pumps and fuel metering units, which
have to be larger for the 97,000-lb.-thrust version.
of the XWB-97 follows the 2011 decision by R-R and Airbus to revise the
A350-1000 thrust requirement from 93,000 lb. to the present 97,000 lb.
To maximize commonality with the baseline XWB and avoid changing the
outer mold line
with an expensive increase in fan diameter, R-R sought
to meet the higher power need by scaling up the core and boosting the
flow. The fan will spin 5% faster, and the annulus at the base of the
fan blades has been redesigned with an inflection to boost the flow
capacity around the spinner.
“We will get more power out of the
core by making it bigger and improve the turbine’s capabilities to run
the engine hotter
,” says Young, adding that the focus is on putting new
technology into the turbine. Changes for the XWB-97 include the use of
next-generation CMS-X4 single-crystal materials and anti-oxidation
coatings in the high-pressure turbine, which will be shroudless for the
first time on a Trent engine.
The turbine disc also will be forged
from a dual microstructure disc that will provide greater stress
capability toward the center of the hub, while exhibiting better creep
resistance toward the tips. Other improvements include a more
sophisticated adaptive bleed system
, which is designed to turn cooling
air bleed off during cruise when not required.
The intermediate (IP)
compressor features a “rising line
” or inner annulus line that increases
in radius, thereby boosting the tip speed of the aft stages. The
high-pressure compressor is derived from the European New Aero Engine
Core Concept program and is connected to the IP by a swan-neck duct.
will be testing one of the 84,000-lb.-thrust (XWB-84) development
engines and putting a selection of ‘97K’ new turbine technology into the
engine, so we can run it as close as possible to XWB conditions,”
Young. The prototype XWB-97 engine is expected to start first runs about
the middle of the year, he adds.