strategic jet engine system design in light of uncertain

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

��

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 = 4.6


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


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

�

��

�

��

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

�

�

�

�

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

��

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

��

�

��

�

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


reduced cost (fewer

graph flattens off due to

rapidly rising fuel con-

sumption

speed

RPK potential due to speed

(ignoring prices)


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


http://www.soton.ac.uk/engineering/research/groups/CED/posters.page | email: [email protected] Engineering & Design Group, University of Southampton, SO17 1BJ, U.K.

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