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Gas Turbine Applications LM 2500, Allison 501, The Plant.

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Presentation on theme: "Gas Turbine Applications LM 2500, Allison 501, The Plant."— Presentation transcript:


2 Gas Turbine Applications LM 2500, Allison 501, The Plant

3 Objectives LM 2500 Gas Turbine Engine - specific components, specifications, systems Allison 501 Gas Turbine Generator Set - purpose and operation Interrelationship of supporting systems and operations Engineering plant lineups

4 Gas Turbine Power Plants Gas generator section Gas generator section Compressor Combustion chamber Gas generator turbine Power section Power section Power turbine

5 LM 2500 In DDGs and CGs, have 4 engines In FFGs, have 2 engines Engines are shock mounted to minimize noise and allow for protection Advantages of LM 2500 Compact & light Easy to maintain & repair Quick start time (~ 1 min)

6 LM 2500

7 LM 2500 Components Starter Pneumatic - driven by pressurized air Compressor 16-stage, axial flow (17:1 compression ratio) Has some controllable pitch vanes to provide proper air flow and prevent stall

8 LM 2500 Components Combustion Chamber Annular design 30 fuel nozzles

9 LM 2500 Components Gas Generator Turbine HP Element only High speed Power Turbine Split shaft to allow varying output speeds while maintaining constant generation of energy 6 sets of nozzles and blades Lower speed than GGT

10 LM 2500 Engine Control Gas Generator Turbine Produces energy available for power turbine Controlled by throttles - alters fuel flow Runs at set continuous RPM Power Turbine Speed depends on quantity of exhaust gases from gas generator turbine & propulsion load Double helical, double reduction, locked train reduction gears

11 LM 2500 Characteristics Stage efficiency = 92.5% R&D: 30,000+ hrs of op-testing Two versions available: LM 2500-20 (22,500 shp) LM 2500-30 (30,000 shp) – USN warships

12 LM 2500 Engine Control Speed Governor Used to prevent power turbine from exceeding speed limit (104%) Reduces fuel to gas generator section which reduces gases to power turbine Overspeed Trip If governor fails, trip secures fuel to LM 2500 to shut it down (108%)

13 CRP Propeller & Propulsion Shafting Shaft is hollow to provide flow of oil to propellers LM 2500 cannot operate at < 5,000 RPM (corresponds to ~11 kts for DDG) Pitch of blades controlled hydraulically through pistons and gears Pitch must be adjusted to go slower than 11 kts

14 In order to go faster than 11 kts, shaft RPM increased In order to go astern, pitch varied to reverse flow Overall purpose Controllable pitch to improve efficiency Reversible to allow for ahead/astern flow with single direction rotation of shaft CRP Propeller & Propulsion Shafting

15 Plant Lineups Disadvantage of gas turbine VERY VERY poor partial load fuel economy LM 2500s connected to reduction gears via pneumatic clutch Three possible lineups Full Power Split Plant Trail Shaft

16 Plant Lineups Full Power Full Power Lineup 2 turbines/shaft with 2 shafts (4 turbines) Max speed > 30+ kts Split Plant Split Plant Lineup 1 turbine/shaft with 2 shafts (2 turbines) Max speed = 30 kts Trail Shaft Trail Shaft Lineup 1 turbine/shaft with 1 shaft (1 turbine) Other shaft windmilling Max speed = 19 kts

17 Air Intake & Exhaust Must minimize space and weight Must keep air inlet losses to a minimum to ensure maximum performance Intake has screens/filters to ensure clean, filtered air at all times

18 Air Intake & Exhaust Exhaust generates thermal and acoustic problems Possible damage to personnel & equipment Increased detection & weapons guidance from heat (IR signature) Silencers and eductor nozzles used to silence and cool exhaust

19 Air Intake & Exhaust

20 Allison 501 Gas Turbine Generator Set (GTGS) Used to generate electricity Three 2000KW GTGS Any two can supply electrical needs of ship Separated by 3 water-tight bulkheads to minimize potential battle damage Single Shaft Waste Heat Boiler Uses heat of exhaust to generate low pressure steam for auxiliary purposes

21 Allison 501

22 Safety Features Automatic Shutdown on: High Vibration Cooling System Failure Module Fire (UV Flame Detection) High Turbine Inlet Temp Low Lube Oil Pressure Power Turbine Overspeed Battle Override

23 Ship Layout

24 Operating Stations

25 Propulsion Plant Comparisons

26 Introduction Overall, various different propulsion designs - to choose, must consider: Operational requirements Construction requirements Manpower requirements Thermodynamic efficiency

27 Design Considerations Minimal size and weight Reliable & easy to maintain Cost efficiency & budget Fuel efficiency over wide power range Shock resistant to handle stress Quiet & safe Manpower & training

28 Conventional Steam Plant Advantages: Efficiency @ cruising speeds Reliability Good performance @ partial loading Usefulness for auxiliary functions Disadvantages Large & bulky w/ large manpower reqs Long start-up time Large fuel storage & low endurance

29 Nuclear Power Plant Advantages Endurance, reliability, speed No air required for combustion No NBC warfare problem Disadvantages High costs & weight for shielding Long startup time Manpower & training requirements Radiological problems

30 Diesel Plant Advantages High efficiency @ all loads Low initial cost and specific fuel cost (SFC) Reliability Few operators needed Disadvantages Capacity limitations & space considerations High maintenance & overhaul High lube oil consumption Noise

31 Gas Turbine Plant Advantages Light weight & compact Short startup time Reliable & quiet High full-load efficiency Disadvantages Large quantities of air (NBC problems) Large fuel storage Low efficiency @ partial loads

32 Hybrid Plants Overall goal: small, more fuel efficient engines for normal ops while retaining ability to shift to high power units when needed Examples: CODAG, CODOG: (Diesel and/or GT) COGAS (RACER): (GT & Steam ) CODAS: (Diesel & Steam)

33 Summary Diesel plant is a hacker! Most efficient Easy to construct and operate Good versatility Gas Turbine with CRP screws is a winning combo Efficient and reliable Good for mass-production missile sponges

34 Summary Most versatile is nuclear plant Tremendous endurance overcomes inefficiency Saves space and energy If you consider fuel storage for other plants, it is actually lighter & less expensive

35 Questions?

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