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1Motori per aeromobili AA 2010-2011Dario Pastrone Dipartimento di Energetica/lato Macchine011 090 4479
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
10
Who drives the propeller ?
Tell me nedeed power
11
Propeller vs Jet Engines
Indicare le idee principali chesi desidera trattare
12
Aircraft Propulsion
Propeller + reciprocating engine
Airbreathing propulsion Gas-turbine propulsion Turboshaft + propeller
Turbojet (+ Afterburner)
Turboprop
Turbofan
Propfan
Ramjet/Scramjet propulsion
13
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
14
Gas-Turbine Engines
The hot pressurized gas can be used To generate power turboshaft To be accelerated in a nozzle turbojet Bothturboprop, turbofan, propfan
15
Gas-Generator components
16
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
17
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
18
Combustor
Primary zone: slow,
high fuel/air ratio
(lean for low emission)Diluition zone
Compressor
Turbine
19
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.
21
Inlets
Credit NASA
22
Nozzle
Credit NASA
23
Afterburner (reheat)
24
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
25
26
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
27
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
28
Goblin (10 16 kN)
Ghost 50
29
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
30
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)
31
GE J79, Variable geometry
To be in service till 2020
Single spool,
67 - 80 kN
32
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
33
Tupolev Tu-144 Konkordsky
Concorde: 1975-2003
1975-78
34
From the Turbojet
Thrust = MassFlowRate * DeltaVelocity Propulsion efficiency High MFR, low DV Turbojet has high WE for subsonic flight Extract power before accelerating flow
35
To the Turbofan and
the Turboprop
36
Aftfan
37
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
38
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
43
44
45
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)
46
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
54
Scramjet
55
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
56
Combined
Engines