Introduction to Aerospace Engineering Lecture slides Challenge the future 1 18-9-2011 Introduction to Aerospace Engineering AE1101ab - Propulsion Delft University of Prof.dr.ir. TechnologyJacco Hoekstra Challenge the future 18-9-2011 Delft University of Technology Challenge the future 11 Propulsion We do not use Anderson’s ch 9 (too difficult for now), but these slides for 1101ab AE1101 Introduction to Aerospace Engineering 3 | xx The propulsion perspective… Gee Bee model ‘R’ Sportster AE1101 Introduction to Aerospace Engineering 4 | xx Wright Flyer required an engine that did not exist • Engine: Wright 4-cylinder 12 - 20 hp water-cooled inline • Weight 150 lbs, 200 lbs with fuel AE1101 Introduction to Aerospace Engineering 5 | xx “Even considering the improvements possible …… the gas turbine could hardly be considered a feasible application to airplanes, mainly because of the difficulty with the stringent weight requirements.” Gas turbine committee, US National Academy of Sciences (1940) Same statement is currently often heard for electrical propulsion! AE1101 Introduction to Aerospace Engineering 6 | xx Theory L T D V0 (m/s) W aircraft- and rocket propulsion ≡ reaction propulsion AE1101 Introduction to Aerospace Engineering 7 | xx You can see this principle in the water rocket. AE1101 Introduction to Aerospace Engineering 8 | xx Theory of air breathing engines V0 (m/s) VJ T mkgs[/] For rocket propulsion we use Tsjolkovski’s rocket equation (covered 1101cd)! AE1101 Introduction to Aerospace Engineering 9 | xx V (m/s) V Theory 0 J T Momentum Equation: ImV=⋅ (En: linear momentum, NL: impuls) dI F = dt (Newton's second law) [kg m/s2](=N) dV →=⋅Fm =⋅ ma dt [kg/s · m/s] (=N) →=TmVV ()j −0 AE1101 Introduction to Aerospace Engineering 10 | xx What Flew or Is Flying Around? Propeller Propulsion Jet Propulsion Human Powered Electrical Engine Airbreathing Engine Rocket Engine Propeller Propulsion Jet Propulsion Piston Engine TurboProp TurboShaft TurboFan TurboJet Ramjet Scramjet AE1101 Introduction to Aerospace Engineering 11 | xx Propeller Propulsion Counter Rotating Rotating AE1101 Introduction to Aerospace Engineering 12 | xx Propeller Propulsion Counter Rotating Rotating Fixed Pitch Variable Pitch Ducted Fan AE1101 Introduction to Aerospace Engineering 13 | xx Propeller Theory R(m) r(m) ω (rad/s) Vrot(m/s) Vrot = Ωω· r AE1101 Introduction to Aerospace Engineering 14 | xx Propeller Theory: Blade is like a wing R(m) S r(m) T ω (rad/s) Useful force: T Thrust (pointing at us) Loss: S Side force (like drag for wing) AE1101 Introduction to Aerospace Engineering 15 | xx Twisted for constant angle of attack ω (rad/s) Large Twist Small Twist Constant angle of attack! AE1101 Introduction to Aerospace Engineering 16 | xx Available Power for thrust t+Δt t T T Δs Work Performed: W= T·Δs[NmorJ] T·Δs Available Power: P = = T·V [Nm/s, J/s or W] a Δt AE1101 Introduction to Aerospace Engineering 17 | xx Available Power t+Δt t T T Speed is V Δs=VΔt Net available Power for thrust: Pa=T V Brake (shaft) Power: Pbr P T V Propulsive Efficiency: η= a = Pbr Pbr AE1101 Introduction to Aerospace Engineering 18 | xx Airbreathing Engines They all work the same way..........in principle Only the details differ. They all have 4 stages: 1. Intake 2. Compression 3. Work 4. Exhaust AE1101 Introduction to Aerospace Engineering 19 | xx Piston Engines What is used in Aviation ? • 2 Stroke Engine Obsolete • 4 Stroke Engine Common • Wankel Engine ‘New’ • Diesel Engine Expected AE1101 Introduction to Aerospace Engineering 20 | xx Combustion Cycle (Otto Cycle) T1 T2 Quasi-static !! dW==Δ⋅⋅ F. ds p A ds Vmax dW=−() p p dV WppdV=−() upper lower ∫ upper lower Vmin AE1101 Introduction to Aerospace Engineering 21 | xx Working Cycle (4 stroke engine) INTAKE COMPRESSION p pV = RT V WORK EXHAUST AE1101 Introduction to Aerospace Engineering 22 | xx Working Cycle (4 stroke engine) INTAKE COMPRESSION WORK EXHAUST p Work [J] V AE1101 Introduction to Aerospace Engineering 23 | xx Throttle control AE1101 Introduction to Aerospace Engineering 24 | xx Piston Engines: In-Line AE1101 Introduction to Aerospace Engineering 25 | xx Piston Engines: Boxer AE1101 Introduction to Aerospace Engineering 26 | xx Piston Engines In-Line Radial V Boxer AE1101 Introduction to Aerospace Engineering 27 | xx Airbreathing Engines Propeller Propulsion Jet Propulsion Piston Engines TurboProp TurboFan TurboJet RamJet TurboShaft AftFan ScramJet By-Pass Engine Turbo Turbo Engine Compound With Propfan Turbo-RamJet RamRocket Engine Continuous Combustion AE1101 Introduction to Aerospace Engineering 28 | xx Continuous Combustion INTAKE COMPRESSION WORK EXHAUST AE1101 Introduction to Aerospace Engineering 29 | xx Continuous Combustion INTAKE COMPRESSION WORK EXHAUST AE1101 Introduction to Aerospace Engineering 30 | xx Ramjet AE1101 Introduction to Aerospace Engineering 31 | xx Pure Jet Engine AE1101 Introduction to Aerospace Engineering 32 | xx Jet Engine With Afterburner AE1101 Introduction to Aerospace Engineering 33 | xx Trading Exhaust Power for Shaft Power INTAKE COMPRESSION WORK EXHAUST AE1101 Introduction to Aerospace Engineering 34 | xx TurboProp/TurboShaft AE1101 Introduction to Aerospace Engineering 35 | xx Turboprop AE1101 Introduction to Aerospace Engineering 36 | xx Turboshaft AE1101 Introduction to Aerospace Engineering 37 | xx Trading Exhaust Power for Shaft Power INTAKE COMPRESSION WORK EXHAUST AE1101 Introduction to Aerospace Engineering 38 | xx TurboFan AE1101 Introduction to Aerospace Engineering 39 | xx This is quite a large duct fan (high bypass flow) Why? AE1101 Introduction to Aerospace Engineering 40 | xx Engine development 1950-1980 Higher Bypass-ratio Bypass airflow (Cold) Core airflow. (Hot) mc B = . mh More air, less velocity Higher propulsive efficiency Can you explain why? AE1101 Introduction to Aerospace Engineering 41 | xx 1 2 2 m V o 1 2 2 m V j Jet efficiency V0 (m/s) V j What is efficiency of jet? m. (kg/s) 1 22 Pjj=−2 mV( V0 ) TmVV=− ()j 0 Pa=T V0 Jet efficiency P a TV mV( j − V00) V η j = 0 = = 1 Pj 1 22 mV +− V V V 2 mV ()j − V0 2 ()()jj00 2 η = What is effect on j V engines of previous slide? 1+ j V0 AE1101 Introduction to Aerospace Engineering 42 | xx 2 η = j V Example of this effect 1+ j V0 In words: by lowering exhaust speed, the efficiency goes from 31% to 54% (amount of energy used for propulsion) AE1101 Introduction to Aerospace Engineering 43 | xx And also less noise due to lower Vj AE1101 Introduction to Aerospace Engineering 44 | xx Engine Development Very big AE1101 Introduction to Aerospace Engineering 45 | xx Engine Applications • Single engine training aircraft: • Piston engine • Low subsonic passenger aircraft: • Turboprop • Concorde (Supersonic): • Pure (straight) jet • Helicopter: • Turboshaft or piston AE1101 Introduction to Aerospace Engineering 46 | xx Two or Four Engines? ETOPS • Extended Twin OPerationS • Engines Turning Or Passengers Swimming • Twin engined airliners restricted to a maximum diversion time (120 to 207 minutes) dependant on strict maintenance and aircraft type. • Crossing some parts of the atlantic and pacific ocean and both poles is (currently) restricted to four engined airliners. AE1101 Introduction to Aerospace Engineering 47 | xx Future air breathing Engines Propeller Propulsion Jet Propulsion Piston Engines TurboProp TurboFan TurboJet RamJet TurboShaft AftFan ScramJet By-Pass Engine Turbo Turbo Turbo-RamJet RamRocket Compound Engine Engine With Propfan AE1101 Introduction to Aerospace Engineering 48 | xx Engines • Pratt & Whitney – PW127B • Turboprop • Aircraft: Fokker 50 • Power: 2750 SHP (x2) 2050 kW (x2) AE1101 Introduction to Aerospace Engineering 49 | xx Engines • Rolls Royce - Tay 650 • Low bypass Turbofan • Aircraft: Fokker 100 • Thrust: 67 kN (x2) • Fan Diameter: 1.14 m • Length: 2.4 m • Bypass Ratio: 3.07 AE1101 Introduction to Aerospace Engineering 50 | xx Engines • General Electric – GE90-115B • High bypass turbofan • Aircraft: Boeing 777 • Thrust: 512 kN (x2) • Fan Diameter: 2.95 m • Length: 4.55 m • Bypass Ratio: 9 Largest and highest thrust engine in the world! AE1101 Introduction to Aerospace Engineering 51 | xx Engines • Rolls Royce – Trent 900 • High bypass turbofan • Aircraft: Airbus 380 • Thrust: 311 kN (x4) • Fan Diameter: 2.95 m • Length: 4.55 m • Bypass Ratio: 8.5 AE1101 Introduction to Aerospace Engineering 52 | xx Engines • Rolls Royce / Snecma Olympus 593 • Pure Turbojet • Aircraft: Concorde • Thrust: 170 kN* (x4) *Using afterburner (take-off and transonic) AE1101 Introduction to Aerospace Engineering 53 | xx Links • www.howstuffworks.com • www.rollsroyce.com • www.ge.com AE1101 Introduction to Aerospace Engineering 54 | xx Beechcraft Super King Air 200 AE1101 Introduction to Aerospace Engineering 55 | xx Pratt & Whitney PT6A-41 • Per engine: 850 Shaft horse power, Pbr=634 kW • Maximum speed at sea level: AE1101 Introduction to Aerospace Engineering 56 | xx.