UNISIM

ENG 201 – AEROSPACE PROPULSION LAB REPORT

KHAIRUL RUSYDI BIN KHAMARUDDIN, H0808022 TEKWANI BUNTI KANAYO, J0806480

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Contents LAB 1.................................................................................................................................. 3 1.1 High Bypass Turbofan vs Others ............................................................................. 3 1.1.1 Turbo fan vs. Turbojet .......................................................................................... 3 1.1.2 Turbofan vs. Turbo prop ...................................................................................... 3 1.1.3 High Bypass Ratio Turbofan vs Low Bypass Ratio Turbofan ............................. 3 1.2 Parametric Analysis ................................................................................................. 4 1.2.1 Single Cycle Analysis for 9056 .......................................................................... 4 1.2.2 Single Cycle Analysis for ABC 9060 ................................................................ 6 1.3 Parametric Study on ABC9056 ................................................................................ 8 1.3.1 Design Bypass Ratio ............................................................................................ 8 1.3.2 Outer Fan Pressure Ratio...................................................................................... 9 1.3.3 Compressor Pressure Ratio ................................................................................ 10 1.4 Optimization .......................................................................................................... 11 LAB 2................................................................................................................................ 12 2.1 Single Cycle Analysis ............................................................................................ 12 2.2.1 Design Bypass Ratio .......................................................................................... 15 2.2.1 Outer Fan Pressure Ratio.................................................................................... 16 2.2.1 Compressor Pressure Ratio ................................................................................ 17 2.3 Optimization .......................................................................................................... 18 2.3.1 Minimizing Fuel Consumption: ......................................................................... 18 2.3.2 Maximizing Net Thrust ..................................................................................... 19 2.3.3 Maximizing Propulsion Efficiency ................................................................... 20

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LAB 1

1.1 High Bypass Turbofan vs Others Discuss why the high bypass turbofan is the most suitable engine type for the B747-300 compared to other engine type such as the turbojet, LOW BPR Turbofan and Turboprob

1.1.1 Turbo fan vs. Turbojet

• Turbofans have a net exhaust speed that is much lower than a turbojet. • This makes them much more efficient at subsonic speeds than turbojets, and

somewhat more efficient at supersonic speeds up to roughly Mach 1.6, but have also been found to be efficient when used with continuous afterburner at Mach 3 and above.

1.1.2 Turbofan vs. Turbo prop

• The advantages and limitations of the turboprop are those of the propeller. o It provides excellent performance advantage for low speed flight and

short field take off. o However, at speeds approaching the speed of sound, the

propeller/rotor loses its aerodynamic efficiency due to compressibility effects.

1.1.3 High Bypass Ratio Turbofan vs Low Bypass Ratio Turbofan

• A high bypass ratio gives a lower (actual) exhaust speed. This reduces the

thrust specific fuel consumption, but reduces the top speed and gives a heavier engine.

• A lower bypass ratio gives a higher exhaust speed, which is needed to sustain higher, usually supersonic, airspeeds. This increases the thrust specific fuel consumption.

• The low–bypass turbofan is more compact, but the high-bypass turbofan can produce much greater thrust, is more fuel efficient, and is much quieter.

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1.2 Parametric Analysis

1.2.1 Single Cycle Analysis for 9056 Cruise Condition ( ALT: 10,500m, 0.86M)

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1.2.2 Single Cycle Analysis for ABC 9060 Cruise Condition ( ALT: 10,500m, 0.86M)

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Findings

• Engine ABC 9056 produces Net Thrust of 50.08, TSFC of 22.9925 and Propulsive Efficiency of 0.7981.

• Engine ABC 9060 produces Net Thrust of 54.76, TSFC of 22.2117 and Propulsive Efficiency of 0.7878.

Based on the findings above;

• Engine ABC 9056 has better propulsive efficiency and TSFC. • Engine ABC 9060 has better Net Thrust. • Therefore we recommend engine ABC 9056 to be selected for the Boeing

747-300 re-engine program due to the potential cost saving involved in the long term due to better propulsive efficiency and TSFC because more thrust can be generated without burning more fuel.

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1.3 Parametric Study on ABC9056

1.3.1 Design Bypass Ratio

Findings:

• From the graph, it shows that Specific Fuel consumption reduces as the Design Bypass ratio is increased from 1 to 6. However after 6 it will increase again

• Propulsive efficiency increases as the design bypass ratio is increased. • Net thrust is decreased as design bypass ratio increases. • Therefore, we have to select a bypass ratio based on the intersection

onf net thrust and propulsive efficiency, which gives a value of 3.8, which gives a lower Specific Fuel Consumption.

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1.3.2 Outer Fan Pressure Ratio

Findings:

• From the graph, it shows that the lower the outer fan pressure ratio, the higher the Specific fuel consumption and also above 1.6.

• Propulsive efficiency decreases as the fan pressure ratio is increased from 1 to 1.6 but increases after that.

• Net thrust increases as the fan pressure ratio is increased from 1 to 1.6 but decreases after that.

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1.3.3 Compressor Pressure Ratio

Findings:

• The highest net thrust is generated when the HP compressor pressure ratio is about 6.

• The optimum Compressor pressure ratio is in between 1 to 1.9.

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1.4 Optimization

Finding: - To minimise Sp. Fuel consumption : - Inner Fan pressure ratio must be more than 3 and Outer fan pressure ratio can be lesser than the design value of 1.8. - The burner exit temperature must be higher than 1600K. - And the Design bypass ratio must be higher than 6.

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LAB 2

2.1 Single Cycle Analysis

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0 .2 .4 .6 .8 1 1.2 1.4 1.6Entropy [kJ/(kg K)]

-250

0

250

500

750

1000

1250

1500

1750

2000En

thal

py [k

J/kg

]

200 kPa 400 kPa 600 kPa 800 kPa 1000 kPa

Pso (ambient) = 22.6 kPa

0 221 25

3

441

43

44 45

495 8

s8

13 18

s18

Ways to improve efficiency and output :

• Raising the overall pressure ratio and turbine rotor inlet temperature in unison makes turbofan more efficient. The combustor entry temperature rises due to the increase in overall pressure ratio of the compression system.

• Therefore, at a fixed fuel flow there is an increase in (HP) turbine rotor inlet temperature. The mixed nozzle temperature is unaffected even though there is a temperature rise across the compressor system and a drop over in the turbine system due to the fact that the same amount of heat is being added to the system.

• However, there is a rise in nozzle pressure as the overall pressure ratio increases faster than the turbine expansion ratio, causing an increase in the burner inlet temperature. The effect is that the net thrust increase while the specific fuel consumption decreases.

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2.2 Parametric Study

2.2.1 Design Bypass Ratio

6 8 10 12 14Design Bypass Ratio

16.5

1717

.518

18.5

1919

.520

20.5

21Sp

. Fue

l Con

sum

ptio

n [g

/(kN

*s)]

.72

.74

.76

.78

.8.8

2.8

4.8

6.8

8.9

Prop

ulsi

ve E

ffici

ency

22.

22.

42.

62.

83

3.2

3.4

3.6

3.8

Net

Thr

ust [

kN]

Design Bypass Ratio = 6 ... 15

Findings:

• From the graph, it shows that Specific Fuel consumption reduces as the Design Bypass ratio is increased from 1 to 12. However after 12 it will increase again

• Propulsive efficiency increases as the design bypass ratio is increased. • Net thrust is decreased as design bypass ratio increases.

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2.2.1 Outer Fan Pressure Ratio

.8 1 1.2 1.4 1.6 1.8 2 2.2Outer Fan Pressure Ratio

1517

.520

22.5

2527

.530

32.5

3537

.5Sp

. Fue

l Con

sum

ptio

n [g

/(kN

*s)]

.74

.76

.78

.8.8

2.8

4.8

6.8

8.9

.92

Prop

ulsi

ve E

ffici

ency

1.6

1.8

22.

22.

42.

62.

83

3.2

3.4

Net

Thr

ust [

kN]

Outer Fan Pressure Ratio = 1 ... 2.8

Findings:

• From the graph, it shows that the lower the outer fan pressure ratio, the higher the Specific fuel consumption. However the Sp. Fuel consumption will increase again after a value of 1.8.

• Propulsive efficiency decreases as the fan pressure ratio is increased from 1 to 1.8 but decreases after that.

• Net thrust decreases as the fan pressure ratio is increased from 1 to 1.6 but increases after that.

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2.2.1 Compressor Pressure Ratio

28 30 32 34 36 38 40HP Compressor Pressure Ratio

1818

.118

.218

.318

.418

.518

.618

.718

.818

.9Sp

. Fue

l Con

sum

ptio

n [g

/(kN

*s)]

.764

4.7

648

.765

2.7

656

.766

.766

4.7

668

.767

2.7

676

.768

Prop

ulsi

ve E

ffici

ency

3.2

3.21

3.22

3.23

3.24

3.25

3.26

3.27

3.28

3.29

Net

Thr

ust [

kN]

HP Compressor Pressure Ratio = 30 ... 39

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2.3 Optimization

2.3.1 Minimizing Fuel Consumption:

From the optimization analysis on minimizing specific fuel consumption, it can be observed that, to achieve this we require:

1. Inner Fan pressure ratio to be between 1 to 2 2. Outer Fan Pressure Ratio lesser than 1.5 3. Burner Exit Temperature lesser than 1800 Design Bypass Ratio to be approximately 15.

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2.3.2 Maximizing Net Thrust

From the optimization analysis on maximizing thrust it can be observed that, to achieve this we require:

1. Inner Fan pressure ratio to be approximately 1.5 2. Outer Fan Pressure Ratio lesser than 3. 3. Burner Exit Temperature more than 20,000 Design Bypass Ratio to be less than 1.

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2.3.3 Maximizing Propulsion Efficiency

From the optimization analysis on maximizing thrust it can be observed that, to achieve this we require:

1. Inner Fan Pressure ratio to be less than 2 2. Outer Fan Pressure Ratio lesser than 1.5 3. Burner Exit Temperature more than 1700 4. Design Bypass Ratio to be approximately 19.

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The table below shows the comparison between the Optimization Analysis. Inner Fan

Pressure Ratio Outer Fan Pressure Ratio

Burner Exit Temperature

Design Bypass Pressure Ratio

Min Fuel Consumption

2 1.5 1800 15

Max Net Thrust 1.5 3 20 000 1 Max Propulsive Efficiency

2 1.5 1700 19

To achieve all three optimization, certain variables have to be compromised. For example to achieve Max Thrust, it is impractical to have a burner exit temperature of 20,000. Therefore, we suggest the values below to achieve all three Optimization.

1. Inner Fan Pressure ratio to be between 1 to 2 2. Outer Fan Pressure Ratio of about 2 3. Burner Exit Temperature approximately 2000 4. Design Bypass Ratio to be approximately 15