Future Trends in Commercial Aviation Engines’ Combustion - Novel Combustion Concepts for Sustainable Energy Development - page 142

NO x because GEnx average margin to CAEP8 is approximately 50 % compared to
5 % for the CF6-80C2; but the technologist has to worry about the slope of takeoff
NO x 10 5 OPR 3 : 97 ) compared to the CF6-80C2 for the GEnx (EINO x ¼ 1 : 08

112 OPR 1 : 59 . However, based on published TAPS technology
development experience, the

given by EINO x ¼ 0 :

'

first generation CFM-TAPS technology s takeoff NO x

is approximately 2 EINO xGEnx whereas that of the GE N + 2 Tech is given by an

unbelievable number 0

EINO xGEnx , as shown in Fig. 27 by two dotted lines
identified, respectively, as 2 and 0.2.
But what does it mean in regard to future NO x stringency regulations, especially
the long-term? This is discussed in Fig. 28 . The aviation engine combustion product
community has worked together in proposing and consenting to future ICAO
stringy regulations because they have not been used to try to eliminate quali

: 2

ed
competitors. Combustion technologists have pursued the long-term goal of 70 %
reduction in takeoff NO x since the early 1970s, Bruce et al. 1977 , which along with
gains in propulsion system ef ciency gave approximately 80 % reduction from the

base CAEE regulation at 30 OPR, namely 20 g NO 2 /kN.
If we follow the trendline of stringencies set by CAEP4, CAEP6, and CAEP8
with the corresponding regulatory values of 67, 59, and 50.1 g NO 2 /kN at 30 OPR
along with the corresponding effective dates of December 31 of 2003, 2007, and
2013, we assume that the next five rounds of NO x stringencies, each 4 year apart

would require the LTO NO x at 30 OPR not to exceed, respectively, 42.6, 36.2, 30.8,
26.2, and 22.2 gm NO 2 /kN. With a 30 % margin from the regulatory standard of
2033, the N + 2 product goal should be 0.7[-37.763 + 2OPR] as shown in Fig. 28
which also summarizes the current status of the best products, namely TALON II,
Trent1000, and GEnx in addition to the current regulation (CAEP/8) and GE N +2
technology as reported by Lee et al. ( 2013 ). We can safely assume that the next
round of TALON-X-based P&W combustion product will be at least as good as

Fig. 28 Characteristic landing - takeoff NO x of the latest engines (viz. GEnx, TALON II, and
Trent1000) and GE N + 2 technology compared to the most recent CAEP regulatory standard (viz.
CAEP/8) and potential CAEP long-term goal, CAEP LT. The N + 2 product goal is set with 30 %
margin to CAEP LT specified as − 9.884 + 2 ˀ