Environmental Engineering Reference
In-Depth Information
pressure ratio for the entire set. Clearly, the Trent1000 appears to be a new brand of
rich-dome concept whose details are not available publicly. Nevertheless, its takeoff
and climbout EINO
x
value are not much different from their counterpart large rich
dome. Therefore, by dividing the average LTO dataset of the RD-L combustors into
two groups (viz. Trent1000 and the remainder identi
ed as RDL-T), the average
LTO NO
x
expressions for the two groups of rich dome combustors are:
Trent1000
¼ 0
:
1292PR
1
:
6327
DP
F
00
2
w
=
R
¼ 0
:
9963
;
RDL
T1000
¼
DP
F
00
1
:
2241
2
:
:
0
6793PR
wR
¼
0
9689 as 1st group
;
It will be interesting to see whether the future TALON-X-based GTF combustors
will belong to the
first group or establish a trend line lower than that of the Trent1000.
A few comments should be made concerning the slope of the NO
x
regulatory
line in addition to speculation about future ICAO NO
x
standards because it impacts
strongly the future combustion technology course. We will focus our discussion for
medium- to large-size engines with OPR
30. The current rich-dome LTO NO
x
data can be approximated by a slope of 2.0. Therefore, instead of across the board
reduction in NO
x
with attendant change in slope (viz. 20 % reduction of CAEP/2
and slope of 1.6 compared to slope of 2 for CAEE or CAEP/1), the future NO
x
regulatory requirements were coined in terms of NO
x
stringency, namely 16.25 %
relative to CAEP/2 (viz. CAEP4) for engines certi
≥
ed after December 31, 2003,
12 % relative to CAEP/4 (viz. CAEP/6) for engines manufactured after December
2007, and the most recent being 15 % relative to CAEP/6, namely CAEP/8 with an
effective date of December 31, 2013 with the attendant equation given by
CAEP
=
2
p
.
In other words, according to the CAEP/8 regulation, aviation engines at 30 OPR
cannot emit more than 50 gm/kN during the ICAO-speci
8
¼
9
:
884
þ
-
ed landing
takeoff cycle
compared to 100 allowed by the
first regulation, namely CAEE.
One could therefore surmise that the potential future regulations, each with addi-
tional 15%NO
x
stringency spaced 4 years apart, are given by the following equations:
CAEP
=
10
¼
17
:
401
þ
2
p
;
CAEP
=
12
¼
23
:
791
þ
2
p
;
CAEP
=
14
¼
29
:
223
þ
2
p
;
CAEP
=
16
¼
33
:
839
þ
2
p
þ
2
p
effective December 2033 giving a regulatory value of 22 gm of NO
2
/kN at
30 OPR compared to 100, 78 % reduction. However, the author prefers to have
30 % margin on the regulatory standard so that when technology is transitioned to
product, there is
Finally, we speculate that the long-term CAEP_LT is CAEP
=
18
¼
37
:
763
flexibility in the process of tradeoffs. This means that the long-term
N + 2 and N + 3 products goal is 15 LTO value at 30 OPR with resulting reduction
of 85 % from the base. But the slope of CAEP_LT will be 2.0 different from the
process used in the technology community. The combustion technology community
fl
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