Gas Turbine Applications LM 2500, Allison 501, The Plant.
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Transcript of Gas Turbine Applications LM 2500, Allison 501, The Plant.
Gas Turbine Gas Turbine ApplicationsApplications
LM 2500,LM 2500,
Allison 501,Allison 501,
The PlantThe Plant
ObjectivesObjectives
• 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
Gas Turbine Power Gas Turbine Power PlantsPlants
• Gas generator Gas generator sectionsection• Compressor• Combustion chamber• Gas generator turbine
• Power Power sectionsection• Power
turbine
LM 2500LM 2500
• In DDG’s and CG’s, have 4 engines• In FFG’s, 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)
LM 2500LM 2500
LM 2500 ComponentsLM 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
LM 2500 ComponentsLM 2500 Components
• Combustion Chamber• Annular design • 30 fuel nozzles
LM 2500 ComponentsLM 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
LM 2500 Engine LM 2500 Engine ControlControl
• 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
LM 2500 LM 2500 CharacteristicsCharacteristics
• 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
LM 2500 Engine LM 2500 Engine ControlControl
• 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%)
CRP Propeller & CRP Propeller & Propulsion ShaftingPropulsion 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
• 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 & CRP Propeller & Propulsion ShaftingPropulsion Shafting
Plant LineupsPlant Lineups
• Disadvantage of gas turbine• VERYVERY poor partial load fuel economy
• LM 2500’s connected to reduction gears via pneumatic clutch
• Three possible lineups• Full Power• Split Plant• Trail Shaft
Plant LineupsPlant Lineups
• Full PowerFull Power Lineup• 2 turbines/shaft with 2 shafts (4 turbines)• Max speed > 30+ kts
• Split PlantSplit Plant Lineup• 1 turbine/shaft with 2 shafts (2 turbines)• Max speed = 30 kts
• Trail ShaftTrail Shaft Lineup• 1 turbine/shaft with 1 shaft (1 turbine)• Other shaft windmilling• Max speed = 19 kts
Air Intake & ExhaustAir 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
Air Intake & ExhaustAir 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
Air Intake & ExhaustAir Intake & Exhaust
Allison 501 Gas Allison 501 Gas Turbine Generator Set Turbine Generator Set
(GTGS)(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
Allison 501Allison 501
Safety FeaturesSafety 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
Ship LayoutShip Layout
Operating StationsOperating Stations
Propulsion Plant Propulsion Plant ComparisonsComparisons
IntroductionIntroduction
• Overall, various different propulsion designs - to choose, must consider:• Operational requirements• Construction requirements• Manpower requirements• Thermodynamic efficiency
Design ConsiderationsDesign 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
Conventional Steam Conventional Steam PlantPlant
• Advantages:• Efficiency @ cruising speeds• Reliability• Good performance @ partial loading• Usefulness for auxiliary functions
• Disadvantages• Large & bulky w/ large manpower req’s• Long start-up time• Large fuel storage & low endurance
Nuclear Power PlantNuclear 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
Diesel PlantDiesel 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
Gas Turbine PlantGas 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
Hybrid PlantsHybrid 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)
SummarySummary
• 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”
SummarySummary
• 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
Questions?Questions?