Jet engines - history and technology��Bingham u3a STEM Group��22nd February 2024�
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Sir Frank Whittle�1907 - 1996
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Gas turbine compressor - radial
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Axial flow compressor blade rows
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Combustion chamber�
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Gas turbine
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What to do with the excess power�
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Early history
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139 BC - Hero's gas turbine
1899 - Curtis patents the first gas turbine engine in the US
1900 - Early development of turbocharger
1903 - First running gas turbine (Norway)
1920 - Designs of axial turbines for driving a propeller
1936 - First industrial gas turbine by Brown Boveri
Hero's gas turbine�concept of jet thrust�
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1899 - Charles Curtis's gas-powered turbine
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First gas turbine, 1903
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Aegidius Elling
Alfred Büchi (1879 – 1959)�Swiss inventor of the turbocharger (1905)�
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Turbocharger design
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Frank Whittle, timeline
1922 to 1948 RAF, apprentice, pilot, Air Commodore
1923 to 1928 RAF Cranwell, School of Technical Training
1930 first patent
1934 patent expires
"This invention is considered unlikely to prove of any practical value to the Royal Air Force in the light of present knowledge. It is considered , in the circumstances, to be of minor value."
W L Tweeedie, Royal Aircraft Establishment, 1935
Gas turbine Brayton cycle
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isentropic change
p/ρ1.4 = const
perfect gas
p = ρRT
p = f1(height)
T = f2(height)
Bernoulli's equation
p0 = p + ½ρV2
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Meanwhile in Germany
1935 Hans von Ohain's first patent
1939 World's first flyable jet aircraft, Heinkel He 178
V-1 flying bomb (Vergeltungswaffe 1)
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Frank Whittle, timeline
1934 to 1937 Cambridge University Engineering Department
1936 formed Power Jets
1937 ground-tests the first jet engine
1941 first flight, Gloster E28/39 exceeds Spitfire performance
Power Jet's workshop
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Rotor assembly of the first experimental engine
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Frank Whittle ground-tests the first jet engine in 1937
(First Whittle patent - 1930)
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pressure ratio 4, bypass ratio 0
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Gloster E28/39
showing location of combustion chambers
First flight
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The Gloster E28/39 jet took off from RAF Cranwell in Lincolnshire for a 17-minute flight on May 15, 1941
Gloster E28/39
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Gloster Meteor (1943 - 1980)
Rolls Royce Derwent (2)
Based on Whittles design, centrifugal/axial
First British jet fighter and only UK jet aircraft in WW2
Top speed 970 km/h, Mach 0.82
Thrust - 1.6 tonnes force
Number aircraft built - 3947
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Frank Whittle, timeline
1944 Power Jets nationalised
1948 Retires from RAF, knighted
1953 Jet, The Story of a Pioneer
Efficiency of heat engines� = work out/heat in�Carnot efficiency = (T2 - T1)/T1
work in = heat out
work out << heat in
waste heat
high
temperature
T2
low
temperature
T1
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Jet engine design�* Newton's second law
thrust* = mass flow x ( Vout - Vin)
residual power = Wturbine - Wcompressor
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Post WW2 design trends
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Increase in turbine inlet temperature
better materials
turbine blade cooling
Increase in by-pass ratio
better propulsive efficiency
introduction of gearbox
lower noise and emissions
improved manufacturing
Increased pressure ratio
axial compressors
2-spool and 3-spool design
use of computational fluid dynamics
Aids to development - experiment
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wind tunnel
compressor cascade
Aids to development - calculation
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Aids to development - flow visualisation
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Aids to development - computational fluid dynamics
Note finer mesh near where velocity gradients are large
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de Haviland Comet, Avon gas turbine
First commercial jet liner
Mach no 0.69
Range 5000 km
Number built - 114
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First axial flow jet engine designed and produced by Rolls-Royce (1952 - 1981)
English Electric Lightning
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Fighter aircraft that served as an interceptor during the 1960s, the 1970s and into the late 1980s
Number built - 337
Avon gas turbine
Mach 2.2, reheat
Avro Vulcan bomber�Olympus gas turbine
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Mach number 0.9
Number built 136
Bristol Olympus was the company's first two-spool, axial-flow turbojet engine, first run in May 1950
Concorde - Olympus gas turbine
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Number built 20
Variable intake to cope with
Mach number of 2.2
Reheat
Rolls Royce RB 211�Airbus 330, Boeing 747
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1972 - 1989
First production 3-spool engine
Mach 0.85
Bypass ratio 4.3
Thrust 18 - 26 tonnes force
Titanium fan blades
Trent ~ 500 engines per year
Rolls Royce RB 211�Bird strike
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Turbine inlet temperature, K
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Turbine blade cooling
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Compressor outlet pressure ratio
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Bypass ratio
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Rolls Royce UltraFan
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thrust - 38 to 50 tonnes force
bypass ratio - 15
pressure ratio - 70:1
14 stage compressor
gearbox power - 64MW
improved efficiency, >10%
40% less NOx
35% less noise
less weight (carbon fibre fan)
UltraFan gearbox
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Frank Whittle, post WW2
1944 Power Jets nationalised
1948 Retires from RAF, knighted
1953 Jet, The Story of a Pioneer
....
1973 Opens Whittle Laboratory, CUED
Frank Whittle's legacy�Whittle Laboratory, 1973
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Frank Whittle, post WW2
1973 Opens Whittle Laboratory, CUED
1976 Moves to USA
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1996 Dies
1998 Ashes transported to Cranwell in Gloster Meteor
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2023
Frank Whittle's legacy
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9th May 2023
The King breaks ground at Cambridge's New Whittle Laboratory
"to encourage the acceleration of sustainable aviation"