1. Gas turbine technology – MTF 171
Concorde:
Recession =>
100 passengers, London <-> New York - less than four hours (six flights per week)
In 1999 maintenance costs consumed 50% of the Concorde's ticket price ($8,000 round trip between New York and London or Paris), vs. 12% for the typical subsonic jet. Paris 2000 – 114 lives lost
Back November 2001
British Oil company president bought 70 return tickets/year
Cruising speed : 2,150 km/h at 16,765 m
v/sqrt(1.4*287*211) = 2.05 cruise mach number
On November 26, 2003 the final Concord flight was flown
WHAT KIND OF ENGINE IS REQUIRED FOR SUCH A MISSION…
Solar – Mercury 50 turbine – regeneration is back to stay?
42 % efficiency. Designed from the outset to be built
with a heat exchanger. Combustor easily accessible => changes
due to different fuels can be accommodated.
r = 9.1
TIT = 1436 K
footprint, maintenance and emissions…
High pressure ratio simple cycles supplanted early configurations using heat exchanger.
WR21 – ICR (InterCooled Recuperated engine = IRA)
Rolls-Royce/Northrop Grumman. 25MW, aeroderivative, RB211
Developed under a US Navy contract, with support from the UK and France
Part load performance improvement.
W1 – test charts
The Frank Whittle engine. Design task is to carry out preliminary
design of this engine during the course. First aircraft gas turbine.
Tomas Grönstedt
Applied mechanics

2. Why read the course ? Head of GE Europe about Scandinavia
“Large pool of talented people that we can tap on to become part of our organization”. Medical area, power generation, aircraft engine, consumer finance
As mechanical engineer, one should know how a jet engine works?
Apply thermodynamics and fluid mechanics
Fun?!
Master thesis opportunities
Previous work include modeling and diagnostics on: PW100 engine JT9D, GT10C, Space launcher model, Cooled cooling in gas turbines, weight estimation, environmental modeling
Aerospace is no longer composed of non-profit organizations
GNP increased 3.8% between , revenue passenger miles 9.5 %
1990:ies GNP: 2.4% and RPM 5.7%
Air traffic growth triple over next 20 years.
GE tops the list of most respected multinational companies.
Apply your thermodynamics and fluid dynamics knowledge.
Boeing returns per share. One share is about 50 dollar.
4,50$ 2007
2,40$ 2006
2,80$ 2005
2,24$ 2004
0,85$ 2003
2,84$ 2002
3,40$ 2001
Boeing is forecasting solid growth

3. Lecture 1 - overview Course introduction
History of the gas turbine
Course content – an overview
Course evaluation process
Revision of some elementary thermodynamics
Gas turbine applications I
Industrial gas turbines and aero derivatives
Land and marine transport
Aircraft propulsion

4. History of the gas turbine
150 BC – Hero, Aeolipile
Chinese began to use rockets as weapons (battle of Kai Keng)
Giovanni Branca developed a stamping mill
Hero: An Egyptian philosopher and mathematician. A real hero = the first gas turbine enthusiast ?
The Chinese began experimenting with the gunpowder filled tubes. At some point, they attached bamboo tubes to arrows and launched them with bows. Soon they discovered that these gunpowder tubes could launch themselves just by the “power” produced from the escaping gas. The true rocket was born.
The stick acted as a simple guidance system that kept the rocket headed in one general direction as it flew through the air. It is not clear how effective these arrows of flying fire were as weapons of destruction, but their psychological effects on the Mongols must have been formidable.
While the Branca machinery represented a significant advancement for its day,
the invention brought only hardship to its creator. Shortly after its introduction,
the boiler exploded and Branca was jailed as a madman.

5. History of the gas turbine
Sir Isaac Newton announces the three laws of motion
Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it (Galileos concept of inertia)
F = ma
For every action there is an equal and opposite reaction.
The three well known laws of motion form the basis for modern propulsion theory.

6. History of the gas turbine
Dr. F. Stolze designed the first true gas turbine engine
multistage axial compressor and turbine turbomachinery
No net power output.
Brayton cycle is loss sensitive! Specific work output = w [J/kg] = difference between two large numbers
Aegidius Elling of Norway built the first successful gas turbine
both rotary compressors and turbines - the first gas turbine with excess power.
Gas turbine cycle is sensitive to losses. Large energy transfer in shafts => small changes
in losses make considerable impact on performance.
Turbine material limits allowable input temperature. For a given pressure ratio turbine
power is proportional to inlet temperature => Turbine inlet temperature (TIT) is critical
parameter. T > 1800 K for military applications.
Efficiency depends on pressure ratio (for the ideal Brayton cycle it only depends on
pressure ratio) => pressure ratio is critical parameter. Pressure ratio of 35 not uncommon.
(lower for high speed military applications). Very modern civil aircraft reach
around 50 in pressure ratio in some operating points.
Note: compression, combustion, expansion occurs in separate units, c.f. Otto/Diesel, which
means that components can be tested and developed separately. More components:
heat exchangers, intercoolers, reheat.

7. The Elling turbine
The process was built as follows: atmospheric air enters through the compressor B, from which a part of the compressed air is bled off at C, constituting the net power output from the engine. The rest of the compressed air passes to the combustion chamber D, where fuel is injected, E. The hot gases under pressure pass through a water cooler F before it enters into the turbine T. The steam produced in the cooler is mixed with the combustion gases in front of the turbine. The mixture of combustion gases and steam had a temperature of about 400°C.

8. The Elling Turbine On the 27th June 1903 Elling wrote in his diary:
“I think I have made the world’s first gas turbine which has given excess power”
In 1933 Elling prophetically wrote:
“When I in 1882 started to work on the gas turbine it was for the sake of the aeronautics and I firmly believe that aeronautics is still waiting for the gas turbine”

9. History - characteristics
High power to weight ratio
Absence of reciprocating parts => balance problems are few
Lubricating oil consumption exceptionally low
Reliability is high (at least it should be possible to make it high)
Obvious application ?!

10. History – gas turbine
Sir Frank Whittle, England patented a design for a gas turbine for jet propulsion.
The specifications of the first jet engine were: Airflow=25 lb/s, Fuel Consumption = 200 gal/hr or 1300 lb/hr, Thrust = 1000 lb, Specific Fuel consumption = 1.3 lb/hr/lb
Powered the Gloster E28/39 Britain on 15 May 1941.
The gas leaves the turbine at high pressure and temperature and is then expanded
to atmospheric pressure in a propelling nozzle to produce a high velocity jet.
The compressor, burner and turbine subsystem is frequently called the gas generator

12. History of the gas turbine
Hans von Ohain (young Ph.D. student in Germany) developed and patented his own engine design.
In 1939:
The aircraft company Ernst Heinkel Aircraft flew the first flight of a jet engine propelled aircraft, the HE178.
The Heinkel jet engine was the brainchild of a brilliant young German scientist named Pabst von Ohain, who was only 25 years old  when the  He-178 made aviation history. The aircraft itself was designed by Heinkel engineers, working under the personal direction of Ernst Heinkel, head of the Heinkel aircraft manufacturing company. That firm financed the development of the He-178 without either the knowledge or financial support of the Nazi government.
Max Hahn was von Ohains star mechanic.
The German jet engine development program was well funded. 1938, Helmut Schelp had to pressure German aero engine companies into accepting funding!!! for studies on jet engines. This should be compared with the every day financial struggle of Frank Whittle.

13. Course overview
History, revision of thermodynamics, introduction and applications. Ideal cycles. Industrial lecturer.
Real cycles. Inclusion of component losses in preliminary design. Elementary nozzle and radial compressor theory. Hand out of Design task 1.
Aircraft engines. Hand in of design task 1.
Turbines. Elementary theory, performance and cooling. Centrifugal compressors 2. Hand out of Design task 2.
Axial compressors. Tutorial using compEDU. Hand in of design task 2.
Gas turbine performance 1 and combustion. Demo of research linear cascade. Hand out of Design task 3.
Rya combined heat and power plant – study visit. Hand in of design task 3.
Written exam, Oral Exam, (suggested date decided by you)
Thermodynamic design
of whole engine
Design turbine
blading
What has changed with new examiner.
More emphasis put on applications and the system – excursions
to illustrate theory
- PBMR, M1 tank, Monterrey III, SR71
- WR21
- Solar 50 Mercury system
Engine services - maintenance
Design tasks.
Simulate
flight

14. Heritage from predecessors
Goals 2003:
Course should provide different learning paths
OH-material based on CRS nomenclature
Build on Thermodynamics course MTF041, Boles, M.A., Cengel, Y.A. nomenclature
Changes after 2003 course:
Hand out design tasks earlier
Limit lectures to 3 hours
Changes from 2004 course:
CompEDU – support axial compressors, maintenance and overhaul
Design task 3 excellent for learning chapter 8 + chapter 9 but time requiring => this year it REPLACES chapter 8 and chapter 9.
Changes from 2005 course:
"gas turbine for beginners...“
Study visit
Learning goals and continuous course evaluation
Changes from 2006 course:
Replace problem 2.3 with exam problem. MATLAB is a learning goal. Review of design task 2. Single “light” industrial lecturer.

15. Continuous course evaluation
2 course representatives
Compensation for effort
Mail addresses stated on course home page
Meeting 1:
Last years meeting protocol
Planned changes are discussed
Goals and structure of course is discussed
Meeting 2:
Week 3-4.
Feedback from group should be presented
Present feedback on homepage
Try to implement changes for the remaining part of the course
Meeting 3:
Course survey handed out during week 7-8 (prior to third meeting)
Student representatives compile the results (prior to third meeting)
Evaluation meeting
Discuss course evaluation and exam results
Protocol by student representatives to be signed by program responsible and course responsible
List of changes to be implemented until next year.
Course responsible summarizes the main issues on the meeting which is put on the course home page

16. Course PM Course Events: Design tasks
Invited lecturer from Volvo Aero on Thursday
12th February - Henrik Ekstrand
Study visit to “Rya CHP plant” (only mandatory event).
Design tasks
Either 10 bonus credits on exam
Entry ticket to oral exam
Literature: ”Gas Turbine Theory”, Cohen, Rogers, Saravanamuttoo
First print 1951…, focus on application. Still the best presentation of the field
A considerable amount of ”sittfläsk” is needed to excel in this course
Book sections are broken down into: Relevant, Important, Very important reading sections

17. First law – conservation of energy
Closed system (ideal gas turbine cycles):
Control volume. Fig (For instance, inlet, compressor, burner, turbine, nozzle):
Flow work performed at the boundary of the open system modifies the conservation of energy equation.
Wflow = F*L = (P*A)*L = P*V =>
specific work flow = P*v
The first law for steady flow systems first appeared in 1859 in a German thermodynamics book written by Gustav Zeuner: the gentleman depicted above.
Flow work is performed. define h = u+pv instead of u
Gustav Zeuner
1859

18. Basic concepts related to second law
Reversible process = process that can be reversed without leaving any trace on the surroundings (5.7 – reversible and irreversible processes)
Reservoir = absorb finite amount of energy without changing temperature (5-2 – thermal energy reservoirs)
Heat engine = receive heat from high-temp source and reject to low-temp. sink. Operate on cycle. Produce work

19. The Carnot Principle
The efficiency of an irreversible heat engine is always less than the efficiency of a reversible one operating between the same two reservoirs.
The efficiencies of all reversible heat engines operating between the same two reservoirs are the same

20. The Carnot Cycle Hard to realize in practice
Standard against which real cycles can be compared

21. Perfect gas and ideal gas
Ideal gas => following equation of state holds
For an ideal gas experiment has shown (Joule’s experiment, U
is independent of v):
Enthalpy is defined:

22. Perfect gas and ideal gas
The specific heat at constant pressure is defined
Since the enthalpy for an ideal gas depends only on T =>
Question: how do you derive cp = cv + R ?
Gamma = cp/cv
Perfect gas => temperature dependence is neglected:

23. Combining the first and second laws:
The first law:
Only pressure-volume work (dw=-Pdv) and for reversible changes
(dqr=Tds):
Using ideal gas law and assuming isentropic process (ds=0 as
well as du=dh - (Pdv+vdP) - by definition of h):
Actually du=Tds-Pdv holds also for irreversible processes!!! Tds takes what is lost in -Pdv.

24. Industrial gas turbines
Aircraft gas turbine is self-explanatory. Industrial = the rest.
Requirements for industrial gas turbines
Long required life ( hours between major overhaul)
Size and weight not as critical as for aircraft gas turbine
Kinetic energy leaving the turbine is ”wasted”

25. Marine and land transportation
Gas turbine characteristics
High power density
High fuel consumption (for low pressure ratios and turbine inlet temperatures) compared to Diesel engine
Poor part load performance
Low noise and low maintenance
Mainly successful in
naval applications
cruise ships
M1 tank
In the early 50:ies optimistic attempts for merchant ships, trains, cars and trucks. Sobering up => succes in naval applications.

26. Marine and land transportation
Example:
Max speed 36 knots, cruise 18 knots. Power requirement ~
Thus, cruise power approx. 1/8 of max power
Combined cycles were developed to avoid part load gas turbine inefficiency
COSAG = COmbined Steam And Gas
CODOG = COmbined Diesel Or Gas
COGAG = COmbined Gas And Gas
Why not CODAG ?

27. Uses of combined configurations
COSAG
Only used on British military ships entering service between 1961 and 1973.
CODOG
Diesel has good cruise fuel economy, but bulkier and larger underwater noise. Small cruise Diesel and a large boost gas turbine is common.
COGAG
Frequent in destroyers (small, fast and lightly armored but heavily armed warship)
The first large vessels to use COGAG was the Soviet "KASHIN" class in 1964 (design calculations appeared on 2003 exam)

28. Naval ships
Four LM2500 GE Marine Gas Turbines (105,000 shp in total) are used on the DDG-51 destroyer
COGAG
31 knots (57 km/h)
American navy has more than 600 engines of the LM2500 type
GE Marine Engines Honors U.S. Navy During 1,000th LM2500 Marine Aero derivative Gas Turbine Ceremony "Our relationship with the U.S. Navy began more than 30 years ago when the first LM2500 was used on the U.S. Navy's GTS Callaghan in Today the LM2500 can be found on the DDG-51, the most modern warship in the world. The engine is also a candidate to power the U.S. Navy's next generation DD21 destroyer," Sparks stated.
GE's continuously infuses new commercial and military aviation technology into this engine. These advancements have enabled the LM2500 to play a significant role in U.S. defense and security interests by powering U.S. Navy ships through every recent major military conflict, and will continue to for many years into the future. In fact, more than 300 Component Improvement Program and Six-Sigma initiatives, plus high quality workmanship from GE's Evendale facility, have added to the LM2500s industry-leading overall reliability and availability.
"We continue to take advantage of the many technological improvements GE employs to keep the LM2500 on the cutting edge of gas turbine technology. These enhancements have enabled the U.S. Navy to grow it's fleet of LM2500s to more than 600 gas turbines in service on a variety of surface combatants, Sealift and supply ships," said the U.S. Navy's Weyman. The LM2500 has proven to be a highly reliable engine for the U.S. Navy, logging more than five million hours at sea. The LM2500 has served on nine classes of ships and is adaptable to a broad range of ships.
Table 1 provides an overview of the U.S. Navy's LM2500 experience.
U.S. Navy LM2500 Fleet
Ship Class # of Ships # of Engines
Callaghan DD DD
DDG CG
FFG
AOE
Sealift
Pegasus
DDG-93  
Spares  
Totals
Worldwide Applications The simple-cycle, two-shaft LM2500 gas turbine is rated at 33,600 shaft horsepower/ 25,050 kilowatts. The gas turbine continues to be the preferred choice with both military and commercial marine customers throughout the world in mechanical and electrical drive applications. To date, the LM2500 has been selected by 27 international navies who employ 366 engines to power their fighting ships, and for 12 commercial marine vessels for five customers. The LM2500 has gained strong international navy recognition. Most recently, the LM2500 was selected by the South African Navy for use in a combined diesel and gas turbine-waterjet and refined propellers configuration on four next-generation MEKO® A-200 corvettes. The Japanese Maritime Self-Defense Forces will also use the LM2500 for its 09DD, 10DD and 11DD Murasame-class destroyers. GE Marine Engines has made significant headway over the past two years in the commercial marine market, especially for cruise ships. The LM2500 will be used on four new Holland America Line cruise ships. The more powerful LM2500+, derived from the LM2500, is being used on new Royal Caribbean and Celebrity Cruises cruise ships. The LM2500 is also used on the world's largest and fastest ferries. Two LM2500s provide the main propulsion for the new Austal-built fast ferry H/F Villum Clausen, Hull 96, which recently set a new record for the longest distance traveled in a 24-hour period by a commercial passenger vessel. The fast ferry is operated by Bornholms Trafikken. There are an additional 1,800 LM2500 gas turbines that have logged 33 million hours in various power generation and mechanical drive applications throughout the world.
Destroyer: small fast lighly armoured but heavily armed warship

29. The Millenium - why gas turbine propulsion ?
Lower and easier maintenance
Gain of volume and weight considerable (900 tons + 50 pax cabins crew's cabins)
Lower noise and vibrations level => better comfort
Reliable, one serious breakdown for 48,800 h. (10 years of commercial exploitation)
A factor of 1000 less need for lubrication's oil!
Gas
Electricity
Steam
Electric power (propulsion + other) by combined cycle (COGES type): gas turbines and steam turbines. Two main alternators (25 MW) are driven by two gas turbines type LM2500. Each gas turbine is equipped with a recuperative boiler which produces the necessary steam to drive a steam turbine (one for the 2 gas turbines) used to drive 9MW alternator => The thermal output is then 43% instead of 39% with gas turbine only.

30. The Millenium cruise ship
The principal advantages of this system are:
- lower and easier maintenance
- gain of volume and weight considerable (about 900 tons and 50 pax cabins + 20 crew's cabins have been added).
- lower noise and vibrations level, so better comfort and lower probability of failure for several equipments
Electric power, for propulsion and other needs of the board, is produced by combined cycle (COGES type): gas turbines and steam turbines. The two main alternators (25 MW, 3,600 tr/min) are driven by two gas turbines type LM2500+ built by General Electric. Each gas turbine is equipped with a recuperative boiler (recuperation of the heat issuing of the combustion of gas in the turbine) which produces the necessary steam to drive a steam turbine (one for the 2 gas turbines) used to drive 9MW alternator.
The thermic output is then 43% instead of 39% with gas turbine only. The previous version of this gas turbine model, the General Electric LM2500 is available for a long time onboard US Navy ships and other Navies (the LM2500+ has a higher power of 25%). Probably higher TIT => exhaust temperature increase => steam generation possible.
They are very reliable turbines, only one serious breakdown for 48,800 hours functioning according statistics.
For Celebrity, these 48,800 hours would represent 10 years of commercial exploitation of the MILLENNIUM.
More, in case of failure, a gas turbine could be able to be replaced in 8 hours only. (a spare one is stored onboard).
Here, it's interesting to notice, gas turbines are (at this time) only interesting in high speed vessels (like warships or quite fast passenger ships - max speed of 25kts and service speed of 24 kts for MILLENNIUM). This is due to higher price of gasoil instead of fuel for diesel engines and better output of diesels at lower power.
The Fastship Lines are building container ships using gas turbines. Max speed 40 kts. Five Trents => 250 MW power.
A factor of 1000 less need for lubrication's oil than corresponding diesel engine requirement.
An electric generator or dynamo for producing alternating currents
An old term for an electric generator that produces alternating current (especially in automobiles)
The Millenium does not have primary boiler(s)/steam turbine(s) system but only primary gas turbine system and THEN, the heat issued of the combustion of gasoil in the two gas turbines is recuperated to heat a boiler which produces steam for a third smaller steam turbine. This steam turbine is only here to improve the output.
Source does not claim use of steam for ”hotel-service”. I think this is something that was forgotten.

31. Water jets
Propulsive water jets range from small aluminum units handling powers up to a few hundred kilowatts to stainless steel units with ratings up to 50MW.
As shown below they can be supplied with steering and reversing systems or as boosters giving ahead thrust only
Water pump connected via drive shaft
To power the water jet pump, the marine jet propulsion engine must be connected via the drive shaft.

32. M1 tank – part load performance
Power plant: AGT-1500 Turbine, 1500hp
Performance:    Maximum speed > 70 km/h
1% efficiency at idle!!!!
High power-to-weight ratio
Use CODOG for extended range
LV100-5 gas turbine engine for the M1A2. The new engine is lighter and smaller with rapid acceleration, quieter running and no visible exhaust.
Air conditioning

33. Aircraft propulsion
Gas turbines are the dominating power plant for aircraft
Piston engines restricted to niche market (light aircraft)
Three major types of engines:
Turbojet (high speed flight)
Turbofan (medium speed flight)
Turboprop (low speed flight)

34. Turboprop – the PT6 Pratt & Whitney Canada
Free turbine
Axial-centrifugal compressor
Reverse-flow combustor
Started 1956 – remains in production kW
Upper right – a Cessna caravan

35. Turbofan engine Fan diameter: 2.95 meters Power A380 maiden flight
Thrust 338kN
(Trent 977)
Turbofans have replaced turbojets for passenger aircraft. Better specific fuel consumption. Less noise.
A380 is the most advanced, spacious and efficient airliner ever conceived. Launched in December and now in its detailed definition phase, the A380 will enter airline service in The world’s only twin-deck, four-aisle airliner with a capacity of 555 passengers.
The A380 can be powered by Trent 900 engines from Rolls-Royce or GP7200 engines from The Engine Alliance (a joint venture between General Electric and Pratt & Whitney). The first Airbus A380 superjumbo is scheduled to make its maiden flight in 2004, with first customer delivery in 2006.
Eight-stage IP compressor; six-stage HP compressor; single annular tiled combustor with 20 fuel injectors; single-stage HP turbine; single-stage IP turbine; five-stage LP turbine.
Civil turbofan (high bpr)

36. Turbofan engine RM12 engine powering the Swedish GRIPEN fighter –
Military turbofan (low bpr)
Total length: 4.04m Weight: 1055Kg Max diameter: 88.4cm (Exhaust nozzle) Inlet diameter: 70.9cm Total compression radio: 27.5:1 Max thrust with afterburner: 80.5kN Max thrust without afterburner: 54.0kN

37. Learning goals Understand the steps in the slides on thermodynamics
Check Cengel and Boles
Check revision questions on next page
Know several different fields of application for industrial gas turbines
What is characteristic of a gas turbine engine when compared with outer power plants?
Know the main types of aircraft gas turbine engines?
Know which speed ranges that are suitable for the different cycles?

38. Revision questions - thermodynamics
Derive cp=cv+R. Hint use definitions of cp, cv, h and the ideal gas law.
Complete the step:
Use cp=cv+R and
Explain why the gas turbine cycle is very sensitive to losses