strategic jet engine system design in light of uncertain
TRANSCRIPT
Strategic jet engine system design in light of uncertain fuel and carbon prices
UTC for Computational EngineeringStephan Langmaak, Prof. James Scanlan and Dr
carbon prices
Stephan Langmaak, Prof. James Scanlan and Drand the Environment and Dr. Stephen Wiseall, Rolls
1. Background1. Background
In 2008, Flightglobal* reported that:
Rolls-Royce is talking up the possibility of a new generation of turboprop-powered aircraft replacing a substantial
proportion of today's narrowbody jets.
The manufacturer believes high oil prices are likely to drive airframers to sacrifice cruise speed for economics.
“The TP400 engine [for the Airbus A400M military transport] is a very efficient propulsion system," R-R Director
Engineering and Technology, Colin Smith, says. “There is a very sound argument to be made for the majority of
the 150-seat market, which flies mostly for less than 1.5h [being turboprop-powered]...“the 150-seat market, which flies mostly for less than 1.5h [being turboprop-powered]...“
*Daly, K., “Rolls-Royce Promotes Turboprop Solution for New Civil Airliners,” Flightglobal, 2008.
3. Methodology
In order to find a strategic engine design that is robust with regard to fuel and carbon price uncertainty in 2030, a SurplusIn order to find a strategic engine design that is robust with regard to fuel and carbon price uncertainty in 2030, a Surplus
the aircraft operator, the aircraft and engine manufacturers and their respective supply chains. The model consists
element.
The flight profile module will simulate typical flights within Europe (Fig. 2) by sampling from the distribution shown
cruise speed’s effect on the modal shift (Fig. 4) which assumes that the market share of the plane is dependent on the
size of the aircraft fleet and the Surplus Value generated. In order to maximize the robustness of the Surplus Value,
(blisks) components installed either within a conventional or a geared turbofan, a turboprop or an open rotor engine
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Figure 2: Simulated flight network
Figure 3: Flight distance distribution Figure 1: Model schematic
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4. Preliminary results
The elements check marked in Fig. 1 were tested in a preliminary study that analyzed the effect of high and low fuel
speed has no significant effect on the fuel consumption over a fixed cruise distance, as long as the speed does not exceed
aircraft (Fig. 8) would be more profitable in terms of Surplus Value in comparison to a conventional turbofan design.
Figure 3: Flight distance distribution Figure 1: Model schematic
Fuel Consumption Vs. Cruise Speed
120%
140%
160%
180%
Fuel Consumption (relative to original A320)
.
Turboprop
Turbofan, Bypass Ratio = 10
Turbofan, Bypass Ratio = 7
Turbofan, Bypass Ratio = 6
Turbofan, Bypass Ratio = 4.6
Turbofan, Bypass Ratio = 3
Pareto Front
wave drag due to shock
waves increases
fuel consumption
drastically
Passenger Kilometers Vs. Cruise Speed in 2030 (Scenario Range)
200%
250%
300%
Revenue Passenger Kilometers (RPK) relative to 2008
Baseline
High Fuel & Carbon Prices
Low Fuel & Carbon Prices increase in traffic due to
reduced cost (fewer
aircraft)
20%
40%
60%
80%
100%
Fuel Consumption (relative to original A320)
Turboprop most fuel efficient Turbofan most fuel efficient
Turboprop or
Turbofan
barely any fuel saving from flying slower
50%
100%
150%
Revenue Passenger Kilometers (RPK) relative to 2008
RPK potential due to speed
(ignoring prices)
increase in traffic due to
reduced cost (fewer
aircraft)
0%
0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95
Cruise Speed (measured relative to the ground at 37000 ft at ISA conditions), Mach
Figure 6: Minimum fuel consumption vs. cruise speed Figure 7: Traffic volume scenario range for 2030
0%
0.35 0.40 0.45 0.50 0.55 0.60
Cruise Speed (measured relative to the ground at 37000 ft at ISA conditions), Mach
http://www.soton.ac.uk/engineering/research/groups/CED/posters.page | email: [email protected] Engineering & Design Group, University of Southampton, SO17 1BJ, U.K.
Strategic jet engine system design in light of uncertain fuel and
James Scanlan and Dr. Andra �s So �bester, Faculty of Engineering James Scanlan and Dr. Andra �s So �bester, Faculty of Engineering Dr. Stephen Wiseall, Rolls-Royce plc.
2. Research question2. Research question
Is there a business case
to change the cruise speed of today’s short-haul 150-seater aircraft
and select an advanced engine technology combination
that produces an engine design that is more robust
to uncertain fuel and carbon prices in 2030
in comparison to today’s turbofans?
3. Methodology
Surplus Value model (Fig. 1) is being created in MATLAB which will effectively calculate the total profit generated bySurplus Value model (Fig. 1) is being created in MATLAB which will effectively calculate the total profit generated by
consists of five modules, including an aircraft design, an engine design, a flight profile, a modal shift and a travel demand
shown in Fig.3. The cost of these flights will partially be driven by the simulated fuel and carbon prices, as well as the
the average speed from door to door. The costs, in turn, will determine the air travel demand (Fig. 5) and hence the
Value, the optimizer will tune the advanced gas turbine technology combination consisting of integrally bladed discs
engine.
40%
50%
60%
70%
80%
90%
100%
Market Share (in term
s of total trips) Plane (812 km/h)
Plane (765 km/h)
Train
Car
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0%
10%
20%
30%
0 100 200 300 400 500 600 700 800 900
Direct Distance, km
Market Share (in term
s of total trips)
Figure 4: Modal shift
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�
�
100%
150%
200%
250%
Relative Demand
Elasticity of -0.96 means:
1% increase in price ~ 0.96% decrease in demand
50% reduction in price = 95% increase in demand
100% increase in price = 49% reduction in demand
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Figure 1: Model schematic
0%
50%
100%
0% 50% 100% 150% 200% 250%
Relative Price
Relative Demand
ln(demand)
ln(price)Elasticity =
Figure 5: European air travel demand elasticity
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4. Preliminary results
fuel and carbon prices on the optimum aircraft design and its ideal cruise speed. Figure 6 indicates that the cruise
exceed Mach 0.77. If oil and CO2 prices were to rise significantly, however, Fig. 7 illustrates that a slower turboprop
. If prices were to reduce though, a faster turbofan aircraft (Fig. 9) would offer a superior business case.
Figure 1: Model schematic Figure 5: European air travel demand elasticity
Passenger Kilometers Vs. Cruise Speed in 2030 (Scenario Range)
traffic volume
depends on fuel
price and cruise
speed
increase in traffic due to
reduced cost (fewer
graph flattens off due to
rapidly rising fuel con-
sumption
speed
RPK potential due to speed
(ignoring prices)
increase in traffic due to
reduced cost (fewer traffic reduces due to
rapidly rising fuel
consumption
Figure 7: Traffic volume scenario range for 2030 Figure 8: Turboprop aircraft
optimized for Mach 0.74
Figure 9: Turbofan aircraft
optimized for Mach 0.88
0.65 0.70 0.75 0.80 0.85 0.90 0.95
Cruise Speed (measured relative to the ground at 37000 ft at ISA conditions), Mach
http://www.soton.ac.uk/engineering/research/groups/CED/posters.page | email: [email protected] Engineering & Design Group, University of Southampton, SO17 1BJ, U.K.