1Motori per aeromobili AA 2010-2011Dario Pastrone Dipartimento di Energetica/lato Macchine011 090 4479

Dario.Pastrone@polito.it

ESAME

Lesame si compone di 2 parti Domande di teoria Commento di esercitazioni svolte

Nel giorno dellappello si decide un calendario di esami. E quindi necessaria la vostra presenza: se non potete venire di persona mandate un vostro delegato. Si cerca di concordare la data, ove necessario si usa lordine alfabetico, a partire dalla lettera estratta.

TESTI (vedi programma del corso)

PROGRAMMA

Conoscenza propulsori aerospaziali con elevato rapporto spinta/peso Airbreathing Progetto di Motori per aeromobili, Controllo prop. Chemical rockets Propulsione spaziale low thrust to weight ratio (ci sarebbero poi Combined/Composite + advanced, hypersonic.)

On-design (performance and preliminary sizing) Off-design (component matching and performance)

2Cosa vedremo in queste prime lezioni.AIRBREATHING

Richiamo prestazioni Descrizione propulsori La Spinta e il suo costo Introduzione La Spinta netta standard S Definizione di Stream force, dinalpia e termini di S Resistenza addizionale (Additional drag or Preentry

thrust) Che positiva Che recuperabile sulla carenatura

Spinta adattata Che la S adattata massima (NB: ugello critico, date

condizioni di volo/funzionamento)

% dei termini di S e guadagno possibile con ladattamento

3Aerospace Propulsion

Reciprocating engines + propeller + compressor (thermojet)

Gas-turbine engines Turboshaft + Propeller (helicopters) Turbojet (+ Afterburner) Turboprop Turbofan Propfan

Ramjet/Scramjet Propulsion Pulsojet, PDE Rocket Propulsion Composite/Combined cycles Other

Jet

propulsion

4 Action-reaction principle (Newton 3 law)

F = m* acc T = mass flow rate* DV

Propulsion:

How can I generate thrust?

5 Action-reaction principle (Newton 3 law) Pushing Energy source, engine, device

Against Working fluid

Working Fluid From outside (air) High mass flow rate,

low acceleration Propeller + engine

Airbreathing engine (air/fuel about 50)

From inside (propellant) Low mass flow, high acceleration Rocket

What I need?

6 Propeller + Reciprocating Engine

Airbreathing propulsion Gas-turbine propulsion

Turboshaft + propeller

Turbojet (+ Afterburner)

Turboprop

Turbofan

Propfan

Ramjet/Scramjet propulsion

Chemical rocket propulsion (next presentation)

7Airfoil

Momentum(flow deflection)

Pressure distribution

8Airfoil

Deflects flow but

Not efficiently for

high turning angles

and transonic speeds

9Propeller

Rotating wing

Limited speed M = 0.5 or 0.6

Separation

Shock waves

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Who drives the propeller ?

Tell me nedeed power

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Propeller vs Jet Engines

Indicare le idee principali chesi desidera trattare

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Aircraft Propulsion

Propeller + reciprocating engine

Airbreathing propulsion Gas-turbine propulsion Turboshaft + propeller

Turbojet (+ Afterburner)

Turboprop

Turbofan

Propfan

Ramjet/Scramjet propulsion

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The core is the gas-generator:

Gas-Turbine Engines

generates hot pressurized gas

looks like a steady-flow version of reciprocating engine

high components efficiency required

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Gas-Turbine Engines

The hot pressurized gas can be used To generate power turboshaft To be accelerated in a nozzle turbojet Bothturboprop, turbofan, propfan

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Gas-Generator components

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Axial

Compressor

and

Turbine

Efficient for high mass flow rates

Axial speed component of fluid almost constant

Compressor may stall: flow turning can be higher in turbine stages larger pressure ratio

Variable inlet guide vane

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Centrifugal Compressor

Only type ready for very first jet engines (large pressure ratio)

Less efficient, higher frontal area, limited staging

Still used for small gas turbines

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Combustor

Primary zone: slow,

high fuel/air ratio

(lean for low emission)Diluition zone

Compressor

Turbine

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Aircraft Propulsion

Propeller + reciprocating engine

Airbreathing propulsion Gas-turbine propulsion Turboshaft + propeller

Turbojet (+ Afterburner)

Turboprop

Turbofan

Propfan

Ramjet/Scramjet propulsion

20

To make a Turbojet

Get a gas generator and add

Inlet (air intake),

Nozzle,

may be an afterburner.

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Inlets

Credit NASA

22

Nozzle

Credit NASA

23

Afterburner (reheat)

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Jet Propulsion 1910

Ghost 50

Compressor

Reciprocating engine Combustor

Nozzle

Coanda-1910

The first jet-airplane, using a

THERMOJET

by Henri Coand, Romanian

Campini Caproni CC.2, 27 Aug 1940

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Jet propulsion 1939 - 44

ME 262 "Schwalbe (1942, 1944)

Jumo 004 (8,8 kN)He S3B (4,4 kN - Hans Von Ohain)

Heinkel He 178, 27 aug 1939

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Jet propulsion 1941 - 46

Frank Whittle W1 3.8 kN

Gloster E28/39 Pioneer (April 14, 1941)Gloster Meteor:1944; 991 km/h in 1946

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Goblin (10 16 kN)

Ghost 50

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First commercial turbojet

Derived from Goblin

Thrust SLS 22.2 kN

Mass-Flow-Rate (MFR) 43 kg/s

Single spool / Centrifugal compressor

Thrust-to-Weight (TW) 2.3

Turbine-Inlet-Temperature (TIT) 1070 K

Ghost 50

Comet : 1952 (now Nimrod)

First flight: 27 July , 1949

Top speed: 810 km/h

Flight altitude: 12800 m

Range: 2400 km

Engines: Ghost 50 Mk1

Passenger seats: 36

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Horizontal supersonic flight

YF-100 using P&W J57 (1953)

YF-100

Fixed geometry, Two spool

50 - 80 kN

Commercial version J57 used on B 707

(1947: X-1 or diving XP-86)

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GE J79, Variable geometry

To be in service till 2020

Single spool,

67 - 80 kN

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Super Sonic Transport (SST)

Two spool

Thrust SLS + AB 169 kN, Dry 138 kN

cruise (18300 m, M=2) 44.6 kN

Mass 3386 kg (TW= 5)

Cruise TSFC 1.21 kg/daN h

Max temperature 1350 K

RR/Snecma Olympus 593

Afterburning turbojet

100 seats, 13 seat-miles per gallon

Takeoff

Cruise

Concorde: 1975-2003

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Tupolev Tu-144 Konkordsky

Concorde: 1975-2003

1975-78

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From the Turbojet

Thrust = MassFlowRate * DeltaVelocity Propulsion efficiency High MFR, low DV Turbojet has high WE for subsonic flight Extract power before accelerating flow

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To the Turbofan and

the Turboprop

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Aftfan

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Turbofan

Air bypass the gas generator Cold/hot mass flow = BPR Low air-speed High BPR (weight and installation losses) High air-speed Low BPR

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39

Turbofan

GE F110, BPR < 1

Supersonic, 100 140 kNBypass flow: 3 stages

Mixing

RR RB211, BPR = 4

Subsonic, 170 250 kNBypass flow: 1 fan

Mixing

40

PW 4000 family

230-440 kN; Fan diameter 2.4, 2.5, 2.8 m

PW 4000 series

41

GE 90 family

Fan > 3 m

(GE, Snecma,

Avio, IHI)

330 - 570 kN

BPR > 9

RR Trent family

240- 460 kN

BPR up to 11

42

Geared Turbofan

PW1000G

Mitsubishi Regional Jet

Bombardier Cseries

Certification due 2012

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44

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Turboprop

1939-1942: Jendrassik Cs-1 world's first Turboprop designed by the Hungarian engineer Gyrgy Jendrassik, not unreliable.

Widely used from 1955 (commuter regional airliners) Vs TurboJet: less fuel, but heavier, more noise and less speed

Vs Reciprocating engine: ligther and smaller (not for low power)

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Prop-fan

Alias UDF (UnDuctedFan) or Open Rotor

Counter-rotating swept blades Up to Mach 0.75 Low specific fuel consumption High cabin noise level

GE-36 UDF McDonnell Douglas MD-81

Progress D-27, Antonov An-70

47

Prop-fanRolls Royce RB2011

Pusher/puller for 150 seat aircraft

Certification due 2017-2018

Pusher less noise: no inlet

interference

Preferred by GE-Snecma

Also geared...

48

Turboshaft

Pratt & Whitney of Canada PT6

1950 Alouette II powered by

Artouste (Turbomeca)

49

Thrust &

Weight

50

Life &

Reliability

51

TSFC

kg/daNh

52

Performance vs Mach number

53

Ramjet

1908 : Patented in France by Ren Lorin. 1933 : ground test of the GIRD-08 ramjet engine was built by Yuri

Pobedonostsev

1949 : Leduc 010 first ramjet-powered aircraft to fly Good performance M = 2 - 4

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Scramjet

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Scramjet flight tests

Nov. 16, 2004 L.A. - The X-43A aircraft flew at a speed of around Mach 9.6(11000 km/h) after a booster rocket took it to around 110,000 feet (33.5 kilometers) and then separated.A modified B-52 airplane had carried the experimental plane and its booster aloft

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Combined

Engines