JET ENGINE MECHANICAL ARRANGEMENT
description
Transcript of JET ENGINE MECHANICAL ARRANGEMENT
JET ENGINE MECHANICAL JET ENGINE MECHANICAL ARRANGEMENTARRANGEMENT
THE WORKING PARTS OF A JET ENGINE
More generally known as ‘GAS TURBINE’‘GAS TURBINE’ Engine
Rolls-Royce AVON – Canberra – 1950’s technologyRolls-Royce AVON – Canberra – 1950’s technology
JET ENGINE MECHANICAL ARRANGEMENTJET ENGINE MECHANICAL ARRANGEMENT
Rolls-Royce AVON - Rolls-Royce AVON - (Graphic Representation)(Graphic Representation)
JET ENGINE MECHANICAL ARRANGEMENTJET ENGINE MECHANICAL ARRANGEMENT
Combustion Combustion Chambers Chambers
(Cans)(Cans)Jet Pipe Jet Pipe
(Exhaust)(Exhaust)
Front Front Engine Engine MountMount
Compressor Compressor Handling Handling
Bleed ValveBleed ValveIntake Anti-Intake Anti-Icing TubeIcing Tube
Rear Rear Compressor Compressor
CaseCase
Front Front Compressor Compressor
CasingCasing
Turbine Turbine SectionSection
Rear Engine Rear Engine MountMount
Oil Oil TankTank
Accessory Accessory GearboxGearbox
Fuel, Oil, and Fuel, Oil, and Hydraulic Pumps, Hydraulic Pumps,
Electrical Generators, Electrical Generators, RPM Governor. RPM Governor.
Turbo-jet = no Bypass DuctTurbo-jet = no Bypass Duct
JET ENGINE MECHANICAL ARRANGEMENTJET ENGINE MECHANICAL ARRANGEMENT
Engine Casings – Static AssemblyEngine Casings – Static Assembly
STATOR VANES
NOZZLE GUIDE VANES (NGV’S)
SUPPORT BEARINGS
COMPRESSOR OUTER
CASINGS
COMBUSTION INNER CASING
COMBUSTION OUTER
CASINGS
COMBUSTION FLAME TUBE
REAR CONE AND SUPPORT
VANES
FRONT BULLET AND
SUPPORT VANES
JET ENGINE MECHANICAL ARRANGEMENTJET ENGINE MECHANICAL ARRANGEMENT
JET ENGINE MECHANICAL ARRANGEMENTJET ENGINE MECHANICAL ARRANGEMENT
Rotating AssemblyRotating Assembly
Compressor BladesCompressor Blades Turbine BladesTurbine Blades
Shaft AssemblyShaft Assembly
The shaded area is called the ‘GAS PATH’. The shaded area is called the ‘GAS PATH’.
JET ENGINE MECHANICAL ARRANGEMENTJET ENGINE MECHANICAL ARRANGEMENT
(We’ll look at what happens to the air passing through the (We’ll look at what happens to the air passing through the GAS PATHGAS PATH in in
Gas Turbine Operation.)Gas Turbine Operation.)
Problem! TProblem! Teemmppeerraatuturree changes cause the shaft and casings to expand and contract changes cause the shaft and casings to expand and contract
But by different amounts!But by different amounts!
This could put tremendous unwanted forces on the casings and shaft leading to failuresThis could put tremendous unwanted forces on the casings and shaft leading to failures
Solution? Its all in the bearings!Solution? Its all in the bearings!
Ambient tempAmbient temp 450 Deg C450 Deg C 2,500 Deg C2,500 Deg C 1,000 Deg C1,000 Deg C Above Above ambientambient
These sections These sections expand firstexpand first
Front Front Bearing Bearing
ChamberChamber
Centre Centre Bearing Bearing
ChamberChamber
Rear Rear Bearing Bearing
ChamberChamber
Bearing ChambersBearing Chambers
Roller Roller BearingBearing
Ball Bearing Ball Bearing (Location Bearing)(Location Bearing)
Roller Roller BearingBearing
JET ENGINE MECHANICAL ARRANGEMENTJET ENGINE MECHANICAL ARRANGEMENT
ShaftShaft
CasingCasing
CasingCasing
Front Front Bearing Bearing
ChamberChamber
Centre Centre Bearing Bearing
ChamberChamber
Rear Rear Bearing Bearing
ChamberChamber
Ball Bearings Ball Bearings Provide Positive Provide Positive Axial LocationAxial Location
Hot Hot sectionsection
JET ENGINE MECHANICAL ARRANGEMENTJET ENGINE MECHANICAL ARRANGEMENT
Representation of jet engine bearing layoutRepresentation of jet engine bearing layout
CasingCasing
CasingCasing
ShaftShaft
JET ENGINE MECHANICAL ARRANGEMENTJET ENGINE MECHANICAL ARRANGEMENT
Shaft and Casing have Shaft and Casing have no differential no differential
movement at this pointmovement at this point
The casing expands first - The casing expands first - pushing the rear outer pushing the rear outer
bearing with itbearing with it
Then, with ‘heat soak’ the Then, with ‘heat soak’ the shaft expandsshaft expands
The same happens at the front with The same happens at the front with pressured air and heat sink from the pressured air and heat sink from the
combustor heating the hardwarecombustor heating the hardware
Representation of jet engine layoutRepresentation of jet engine layout
The engine is actually designed to dimensions based on The engine is actually designed to dimensions based on normal operating temperaturesnormal operating temperatures
JET ENGINE COMBUSTOR JET ENGINE COMBUSTOR OPERATIONOPERATION
WHERE THE POWER IS PRODUCED
FUEL IS MIXED WITH AIR BEFORE ENTERING THE CYLINDERS
THE FUEL/AIR MIXTURE IS THEN COMPRESSED
THEN IT IS IGNITED BY A SPARK
IN A PISTON ENGINE: -
ONCE FOR TWO REVS OF THE ENGINE (IN THE 4 STROKE CYCLE)
AIR IS COMPRESSED AND FORCED INTO THE COMBUSTOR FIRST
THEN THE FUEL IS SPRAYED IN UNDER PRESSURE
IT IS THEN IGNITED BY A SPARK (BUT ONLY ONCE FOR STARTING)
IN A JET ENGINE: -
COMBUSTION IS THEN CONTINUOUS WHILST THE ENGINE IS RUNNING
JET ENGINE – Combustion ProcessJET ENGINE – Combustion Process
THE COMBUSTION PROCESS
THE SAME AS A PLUMBERS BLOW TORCH!
We’re going to look in detail at
what happens here
But first we’ll look at the layoutof the combustion system
JET ENGINE – Combustor LayoutJET ENGINE – Combustor Layout
EACH CAN HAS A FUEL SPRAY NOZZLE (FSN)
COMBUSTOR LAYOUT – (ALSO HISTORICAL DEVELOPMENT)
INDIVIDUAL COMBUSTORS – ‘CANS’1st JET ENGINES
WHITTLE ETC
OUTERCASING INNER
CASING
ENGINE STRUCTURE
AND SHAFTS
FLAME CONTAINED WITHIN THIS TUBE
‘FLAME-TUBE’
JET ENGINE – Combustor LayoutJET ENGINE – Combustor Layout
COMBUSTOR LAYOUT – (ALSO HISTORICAL DEVELOPMENT)
CANS CONNECTED TOGETHER TO EQUALISE PRESSURES
AND
TO SPREAD THE FLAME ON START UP
TYPICAL OF DART SERIES
TURBO PROPS
IGNITERS
JET ENGINE – Combustor LayoutJET ENGINE – Combustor Layout
JET ENGINE COMBUSTER OPERATIONJET ENGINE COMBUSTER OPERATION
COMBUSTOR LAYOUT ‘CAN-ANNULAR’ LAYOUT
ANNULAR OUTER
CASING
ALSO FORMS THE ENGINE STRUCTURE
IGNITERS
INDIVIDUAL CANS WITH INTER-
CONNECTORS
TYPICAL OF SPEY &TAY
BYPASS ENGINES
JET ENGINE – Combustor LayoutJET ENGINE – Combustor Layout
JET ENGINE COMBUSTER OPERATIONJET ENGINE COMBUSTER OPERATION
COMBUSTOR LAYOUT ANNULAR LAYOUT
ANNULAR OUTER
CASING
ANNULAR INNER CASING
ALLOWS MORE FSN’S TO BE FITTED
GIVES EVEN TEMPERATURE FACE TO TURBINE BLADES
THE LAYOUT OF CHOICE FOR
MODERN BYPASS ENGINES
JET ENGINE – Combustor LayoutJET ENGINE – Combustor Layout
JET ENGINE COMBUSTER OPERATIONJET ENGINE COMBUSTER OPERATION
THE CROSS SECTION OF ALL THESE LAYOUTS IS VIRTUALLY IDENTICAL
AND THEREFORE SO IS THE AIRFLOW!
JET ENGINE – Combustor LayoutJET ENGINE – Combustor Layout
JET ENGINE – Combustion ProcessJET ENGINE – Combustion Process
Fuel Feed
Outer Combustion Casing
1st Stage NGV’s
18% Vortex Flow
Recirculating Vortex
Inner Flame Tube
82% Cooling Flow
Any Questions?Any Questions?