STEAM ENGINE

• GROUP MEMBERS :

• MUHAMMAD KASHIF (UW-09-ME-BE-017)

• ROMAN KALVIN (UW-09-ME-BE-045)

• HAFIZ AZHAR HAYAT (UW-09-ME-BE-022)

• REHAN SALEEM BHUTTO(UW-09-ME-BE-016)

• MUHAMMAD HASHIM(UW-09-ME-BE-046)

• MUHAMMAD NAUMAN RASHEED(UW-09-ME-BE-014)

• MUHAMMAD HAMMAD HABIB(UW-09-ME-BE-043)

• MALIK AHTISHAM ARIF(UW-09-ME-BE-040)

• ABDUL GHAFOOR ABBASI(UW-09-ME-BE-029)

• MUHAMMAD ASHIQ(UW-09-ME-BE-037)

• USMAN AHMAD(UW-09-ME-BE-047)

• MUZAMMAL SHAHID (UW-09-ME-BE-051)

•

*External combustion engine. *Internal combustion engine.

-Ex: steam engine -Ex: car engine

What is an engine?

Types of engines:

- a machine which converts chemical energy into mechanical energy

Figure source:http://www.tpub.com/machines/12.htm

DIFFERENCE

• The main difference is where the combustion takes places. In IC engines fuel combustion takes place inside the cylinder, whereas in EC engines it takes place outside the engine cylinder.

• The temperature and pressure in an IC engines is much higher than those of EC engines.

• IC engines are made of materials that are better resistant to heat and pressure than in EC engines.

• IC engine cylinder is usually made of an iron alloy that contains nickel and molybdenum. Aluminum is used whenever weight is a consideration . EC engine is mainly made of cast iron

• In IC engines the piston is directly connected to connecting rod, whereas in an EC engine there is a stuffing box.

EC ENGINE IC ENGINE

INTRODUCTION:• Steam engines are typically external combustion engines• A steam engine is a heat engine that performs mechanical

work using steam as its working fluid.

HISTORY OF STEAM ENGINE

• Inventors used experimental devices, such as the rudimentary steam turbine device described by Taqi al-Din in 1551 and Giovanni Branca in 1629, to demonstrate the properties of steam.

• The first practical steam-powered 'engine' was a water pump, developed in 1698 by Thomas Savery. It proved only to have a limited lift height and was prone to boiler explosions, but it still received some use for mines and pumping stations.

• The first commercially successful engine, the atmospheric engine, invented by Thomas Newcomen did not appear until 1712. Newcomen's engine was relatively inefficient, and in most cases was only used for pumping water.

HISTORY OF STEAM ENGINE James Watt developed an improved version of Newcomen's engine

between 1763 and 1775 which used 75% less coal than Newcomen's, and was hence much cheaper to run. Watt proceeded to develop his engine further, modifying it to provide a rotary motion suitable for driving factory machinery.

Early engines were "atmospheric", meaning that they were powered by the vacuum generated by condensing steam instead of the pressure of expanding steam. Cylinders had to be large, as the only usable force acting on them was atmospheric pressure. Steam was only used to compensate for the atmosphere allowing the piston to move back to its starting position. Even if pressured steam had been available, it could not do any work (push) against the chain connecting the piston to the beam.

EARLY WATT STEAM PUMPING ENGINE.

CLASSSIFICATION OF STEAM ENGINE:

According to number of working strokes :

According to position of the cylinder :

According to speed of crank shaft :

According to type of exhaust :

According to the expansion of the steam.

According to the method of governing employed

ACCORDING TO NUMBER OF WORKING STROKES :

• Single acting steam engine :

In this steam is admitted from one side of piston & one working stroke is produced during each revolution of crank.

ACCORDING TO NUMBER OF WORKING STROKES :

• Double acting steam engine :

In this steam is admitted from both sides of piston & two working stroke is produced during each revolution of crank.

ACCORDING TO POSITION OF THE CYLINDER

• HORIZONTAL STEAM ENGINE

When the axis of cylinder is horizontal

ACCORDING TO POSITION OF THE CYLINDER

• VERTICAL STEAM ENGINE

When the axis of

cylinder is vertical .

ACCORDING TO SPEED OF CRANK SHAFT

• SLOW SPEED STEAM ENGINE When speed of crank shaft is less than 100 rpm

• MEDIUM SPEED STEAM ENGINE When speed of crank shaft is between 100 rpm & 250 rpm

• HIGH SPEED STEAM ENGINE When speed of crank shaft is more than 250 rpm

ACCORDING TO TYPE OF EXHAUST :

• CONDENSING STEAM ENGINE

When the steam is reconverted in to water after passing the cylinder .

• NON CONDENSING STEAM ENGINE

When the steam is exhausted in to atmosphere after passing the cylinder .

ACCORDING TO THE METHOD OF GOVERNING EMPLOYED:

• THROTTLING STEAM ENGINE:

When the engine speed is controlled by a throttle valve in the steam pipe

• AUTOMATIC CUT –OFF STEAM ENGINE: When the engine speed is controlled by an automatic cut-off governor in the steam pipe

ACCORDING TO THE EXPANSION OF STEA M IN THE ENGINE CYLINDER

• SIMPLE STEAM ENGINE:

• When the expansion of the steam is carried out in a single cylinder and then exhausted in to the atmosphere or a condenser is called simple steam engine.

COMPOUND STEAM ENGINE :

• When the expansion of the steam is completed in two or more cylinders is known as compound steam engine

OTHER TYPES OF STEAM ENGINES• Compounding Engines

• Multiple Expansion Engines

• Uniflow Engines

• Turbine Engines

• Rotary Steam Engines

• Jet-type Steam Engines

• Rocket-type Steam Engines

R ear B earin g

F orw ard B earin g

C ran k S h a ft

C ran k S u p p ort

C ran k S u p p ort A ssem b lyS u b -A ssem b ly

P is ton P in

C on n ec tin g R od

P is ton

P is ton A ssem b lyS u b -A ssem b ly

S c rew # 2

S c rew # 1

C ylin d er H ead G aske t

C ylin d er H ead

C ylin d er B lock

R ear C ran k C ase

M isc P arts A ttach edD u rin g F in a l A ssem b ly

E n g in eA ssem b ly

MAIN PARTS:

Frame . Cylinder . Steam Chest . D Slide valve . Inlet & Exhaust

ports . Piston . Piston rings . Cross Head . Connecting Rod . Crank Shaft . Eccentric .

Fly Wheel . Valve Rod . Piston Rod . Governor .

COPYRIGHT ROTAX FLYING CLUB 2001 (C) 23

PISTON:

• A cylindrical disc moves to and fro in cylinder with steam pressure.

• Transfer energy to the crankshaft

• Control expansion under warm-up

COPYRIGHT ROTAX FLYING CLUB 2001 (C) 24

NORMAL PISTONS

• Deposits vary from oil ash, brown, tan, to black/brown. Light color denotes higher cylinder temperatures.

• Light scoring is normal, varnish from blow-by gas is normal

COPYRIGHT ROTAX FLYING CLUB 2001 (C) 25

COLD SEIZURE

• Thermo-imbalance of piston and cylinder

• Lack of warm-up

• Excessive temperature difference inlet to outlet on engine.

COPYRIGHT ROTAX FLYING CLUB 2001 (C) 26

HEAT SEIZURE

• Excessive heat, over 1200F/650C EGT

• Lean jetting or adjustments on carb

• Incorrect loading on propeller allowing excessive RPM

It is a heavy cast iron part,which supports all stationary as well as moving parts and hold them in proper position.it genenerally rest on engine foundation

CYLINDER:

• It is also a cast iron cylindrical hallow vessel , in which the piston moves to and fro under the steam pressure.

• Both the end of cylinder are closed and made steam tight.

STEAM CHEST

• It is casted as integral part of cylinder. It supply steam to the cylinder with the movement of D slide valve.

D SLIDE VALVE

• It moves in a steam chest with simple harmonic motion ,its function is to exhaust steam from cylinder at proper movement.

INLET AND EXHAUST PORTS

• These are holes provided in the body of cylinder for the movement of steam. Initially steam enters through inlet port and after doing its work in the cylinder ,is exhausted through exhaust port.

PISTON RING

A piston ring is an open-ended ring that fits into a groove on the outer diameter of a piston in a reciprocating engine such as an internal combustion engine or steam engine.

CROSS HEAD

• It is a link between piston rod and connecting rod. Its function is to guide motion of the piston rod and to prevent it from bending.

CONNECTING ROD

• It is made of forge steel,its one end is connected to cross head and other to the crank.it convert reciprocating motion of the poiston into rotary motion of crank

CRANK SHAFT

• It is the main shaft of the engine having a crank. The crank works on the lever principle and produces rotary motion of the shaft.

ECCENTRIC

• It is fitted to the crank shaft .its function is to provide the reciprocating motion to the slide valve

PISTON ROD

• It is a circular rod which is connecting to the piston on one side and cross head to the other. Its function is to transfer motion from piston to cross head

GOVERNOR

• It is a device to keep the engine speed more or less uniform at all load condition by the supply of steam.

FLY WHEEL

• It is a heavy cast iron wheel ,mounted on crank shaft. Its function is to prevent fluctuation of engine.

STEAM BOILER

IT IS A DEVICE WHICH IS USED TO CONVERT WATER IN TO STEAM.

RANKINE CYCLE

RANKINE CYCLE Process 1-2: The working fluid is pumped from low to high pressure, as the fluid is a liquid at this

stage the pump requires little input energy. Process 2-3: The high pressure liquid enters a boiler where it is heated at constant pressure by an

external heat source to become a dry saturated vapor. Process 3-4: The dry saturated vapor expands through a turbine, generating power. This decreases

the temperature and pressure of the vapor, and some condensation may occur. Process 4-1: The wet vapor then enters a condenser where it is condensed at a constant pressure

and temperature to become a saturated liquid. The pressure and temperature of the condenser is fixed by the temperature of the cooling coils as the fluid is undergoing a phase-change.

BASIC OPERATION OF A SIMPLE RECIPROCATING STEAM ENGINE

• Heat is obtained from fuel burnt in a closed firebox • The heat is transferred to the water in a pressurized boiler,

ultimately boiling the water and transforming it into saturated steam. Steam in its saturated state is always produced at the temperature of the boiling water, which in turn depends on the steam pressure on the water surface within the boiler.

• The steam is transferred to the motor unit which uses it to push on a piston sliding inside a cylinder to power machinery.

• The used, cooler, lower pressure steam is exhausted to atmosphere.

HOW TO START STEAM ENGINE

• THINGS YOU'LL NEED:

Engine

Water

Fuel

Mentholated spirits

Oil

Matches

• Add hot water carefully into the hole at the top of the boiler making sure to fill only to the level indicted; too full and you can flood the engine. Using hot water will decrease the amount of time it takes to get the engine started, as it won't have to waste valuable energy heating up the water. There should be a water level glass that indicates when the water has reached maximum capacity.

• Push water level plug into the water level hole and secure in place. Not all models have this feature. Spirit burning engines proceed to Step 4 and for modern burners, proceed to Step 3.

• Place a fuel tablet in the burner tray. You may need a knife to cut the tablet down to the size of your tray. Fuel tablets can be purchased at any good model shop or online.

PROCESS

PROCESS

• Pour mentholated spirits into the gauze-style burner of your older model engine. Be sure to drip directly into the top of the burner. The amount of spirits is a judgment call you must make based on the size of your engine.

• Lubricate all moving parts of the engine with lubricating oil. Specially made Mamod oil exists but any engine oil is acceptable.

• Complete a quick check ensuring the water level cap and safety valve are tight and lube the flywheel with oil.

• Ignite the fuel on the burner and place under the engine's boiler. Let things warm up and enjoy the show.

Double Piston Stroke

WORKING OF STEAM ENGINE

FIRST STROKESTEAM FROM THE BOILER ENTERS THE STEAM CHEST AND IS ADMITTED TO THE FRONT END OF THE CYLINDER BY A VALVE SLIDE (ILLUSTRATED IN BLUE). THE HIGH PRESSURE STEAM PRESSES THE PISTON BACKWARD, DRIVING THE ENGINE WHEELS AROUND ONE HALF TURN.

EXHAUST• At the end of the piston stroke, the valve shifts, allowing the remaining steam

pressure to escape through the exhaust port underneath valve slide (in blue). The pressure escapes in a quick burst which gives the engine its characteristic sound.

SECOND STROKEAT THE SAME TIME, THE VALVE SLIDE BEGINS ADMITTING HIGH PRESSURE STEAM TO THE BACK END OF THE CYLINDER. THIS PRESSES THE PISTON FORWARD, PULLING THE ENGINE WHEELS AROUND ANOTHER HALF TURN.

EXHAUSTEXHAUSTAT THE END OF THE SECOND STROKE, THE STEAM IS RELEASED FROM THE REAR PORTION OF THE CYLINDER .

Thank S

Any question????