5. Engines

Vocabulary

steam-engine – паровой двигатель

high-speed – высокоскоростной

to invent – изобретать

boiler – котел

to explode – взрываться

piston – поршень

locomotive – паровоз

Text

The steam-engine was the first high-speed engine ever invented. The principle of the steam-engine is simple. When water is boiled, it changes into steam. If steam is kept inside a boiler, it pushes against the sides. The more the steam is heated, the more pressure it has. (If the steam pressure becomes too high, the boiler may explode.) It is the pressure of steam that we put to work.

A steam-engine has two important parts. One is a boiler where a fire turns water into steam. The steam goes through a pipe to the other important part - the steam chest with a cylinder and a piston in it.

Inside a steam-engine

Steam enters one end of the cylinder and pushes the piston back. Then it enters the other end, pushing the piston forward again.

How is it done? The thing is that there are valves, or openings, in the steam chest. These valves let steam in first at one end, then at the other. As the piston moves in the cylinder, it opens and closes the valves automatically, so that fresh steam enters just when the piston has reached the end of its stroke.

After the steam has pushed the piston, it is cooler and has less energy. As the piston is pushed again by fresh steam the used steam goes out through another valve.

A rod from the piston is connected to a wheel. When the piston goes forward, the wheel makes half a turn. As the piston goes back, the wheel makes the other half a turn.

There was a time when steam-engines were widely used. We even had steam cars. But now steam-engines arc mostly used in locomotives, and fewer steam locomotives are made each year. Some day steam-engines will be only in museums.

Exercises

1. Read the following words:

machines, cylinder, powerful, something, engine, fuel, rotor, pressure, steam-engine.

2. Answer the question:

   1. What was the first engine?

   2. Into what does water change when it is boiled?

   3. When has steam more pressure?

   4. When may the boiler explode?

   5. What main parts does a steam-engine consist of?

   6. What is the function of a wheel?

   7. When were steam-engines widely used?

   8. Where are they mostly used now?

   9. Do you think that some day steam engines will be only in museums?

3. Retell the text.

Vocabulary

example – пример

to convert – превращать

external combustion engine – двигатель наружного сгорания

internal combustion engine – двигатель внутреннего сгорания

cylinder – цилиндр, газобаллон

safety valve – предохранительный клапан

steam chest – паровая коробка

slide valve – золотник

flywheel – маховик

to cover – прикрывать, покрывать

steam port – паровое отверстие

towards – к, по направлению

to convey – перевозить, переправлять

crank shaft – коленчатый вал

to maintain – поддерживать, сохранять

speed governer – регулятор скорости

gasoline – газолин, бензин

diesel – дизельное топливо

successfully – успешно

a turn – оборот

alternatively – поочередно, друг за другом

Text

The steam engine is an example of a heat engine. Heat engines are those which convert heat energy into mechanical work. They are of two types: external combustion engines and internal combustion engines. Steam engine is an external combustion engine. This means that fuel is burned outside the cylinder that produces power. The engine of automobiles are internal combustion engines i.e. the fuel burns inside the cylinder.

The steam engine consists of a boiler, safety valve, cylinder, steam chest, slide valve and a flywheel. Super-heated steam is made to pass into the steam chest through steam pipe from the boiler. The slide valve covers and opens the steam ports, A and B, alternatively and thus allows the team to pass through only one of them at a time into the cylinder. In the figure slide valve’S. V.’ has been shown at the right side and the steam port A is opened. Thus the steam goes into the left hand portion of the cylinder. It pushes the piston to the right. At this instant port B opens because the slide valve is pushed towards left by the action of the connecting rods. Now the steam enters the port B and pushes the piston towards left-hand side. This process goes on repeating and cycle of operation continues.

The motion of piston is conveyed to a heavy flywheel fixed to the crank shaft. It keeps on moving due to its high moment of inertia and thus keeps the train in motion. The speed of the steam engine is maintained constant by means of a speed governor. It regulates the supply of steam into the steam chest with the help of a valve provided with the steam pipe.

Today, most of the functions of steam engines have been taken over by internal combustion engines fueled by gasoline or diesel. Now, even electrically operated engines have also been developed and are being used successfully in the railway locomotives.

Exercises

1. Read the words:

mechanical work, external combustion, internal combustion, cylinder, automobile, steam, slide valve.

2. Answer the questions:

   1. What is the function of heat engines?

   2. What types of heat engines do you know?

   3. What type of engine is the engine of automobiles?

   4. What are the main parts of any steam-engine?

   5. What is the function of the slide valve?

   6. What fuels are used for steam-engines?

   7. Where are steam-engines being used successfully?

3. Read and translate the article.

Vocabulary

carburetter – карбюратор

to compress – сжимать, сдавливать

crankshaft – коленчатый вал

to expand – расширяться

to explode – взрывать (ся)

explosion – взрыв

gasoline-engine – бензиновый двигатель

to mix – смешивать

mixture – смесь

oil – нефть

petrol – бензин, бензиновый

spark – искра, вспышка

spark plug – запальная свеча

vapour – пары

A gasoline-engine

wood – дерево (материал)

petrol – бензин

to revolve – вращаться

stroke – ход, взмах, удар

sucking in – всасывая

crank-shaft – коленчатый вал

the cycle – цикл

smoothly and steadily – плавно и равномерно

Inside a gasoline-engine.

Text

When wood, coal, oil or petrol burns, gases are formed. In gasoline-engines these gases push the pistons. The fuel in gasoline-engines is petrol. Petrol vapour and air are mixed in the carburetter before they go into the cylinder. In the cylinder this mixture of gases is exploded by a spark. When things are heated, they become bigger. That is what happens to the gases in the cylinder during the explosion. The heat is so great that the gases expand very quickly. So they push the piston that revolves the crankshaft to which it is connected. The explosions come fast - one after the other. So millions and millions of explosions take place every day in the millions of gasoline-engines that run cars and planes and boats.

In most gasoline-engines the piston (as it moves up and clown in the cylinder) pushes, or gives power, in only one stroke out of four.

In the first stroke the piston moves down the cylinder, sucking in a mixture of gases through an opening, or valve.

The valve shuts and in the next stroke the piston moves up, compressing the gases. At this moment a spark runs across the spark plug, exploding the mixture.

The gases from the explosion are heated greatly, and they push the piston down. This is the third or power stroke, the stroke that really works, revolving the crankshaft.

In the last, fourth, stroke before the cycle starts again, the piston moves up, pushing the used gases out through another valve.

The revolving crankshaft sends each piston up and down till the next power stroke.

When an engine has more than one cylinder, the power strokes come one after another-so the engine can turn wheels or propellers smoothly and steadily.3

Cars usually have 4 to 8 cylinders. Large airplane engines may have 20, 24 or even 28 cylinders.

Exercises

1. Read the words:

smoothly and steadily, stroke, piston, mixture, to explode, crank-shaft, cylinder, valve, power, explosion, carburetter.

2. Answer the questions:

   1. What are formed when fossil fuels burn?

   2. What is the fuel in gasoline-engines?

   3. Where does mixture of petrol vapour and air appear?

   4. Where is this mixture of gases exploded?

   5. What happens to the gases in the cylinder?

   6. What makes cars, planes and boats to run?

   7. What is the function piston in the cylinder?

   8. How many cylinders have cars?

   9. How many cylinders may have large airplanes?

Vocabulary

blower – воздуходувка

compressed air – сжатый воздух

diesel engine – двигатель дизеля

generator – генератор

to inject – впускать

pump – насос

A diesel engine A diesel engine (named after its inventor) is like a gasoline-engine but simpler.

Text

Diesel engines are usually larger and can do more work. The fuel used in a diesel engine is oil.

In a diesel engine, only air is blown into the cylinder. It is compressed by the piston till it becomes very hot. At that moment oil is injected into the compressed air. The air is so hot that the oil explodes immediately. It does not need spark plugs. The explosions push the pistons and turn the crankshaft as in gasoline-engines.

Diesel engines can be four-stroke ones and two-stroke ones. In two-stroke engines every second stroke (and not every fourth as in four-stroke engines) is a power stroke. This is a real advantage as the two-stroke engine gives more power.

In a two-stroke diesel, as the piston moves down, a powerful blower blows air through valves into the cylinder. As it comes in, the air pushes out the used gases from the previous explosion. The valves shut and the piston moves up, compressing the air and raising its temperature .to about 1000° F (537,8° C).

At that moment oil is injected by a powerful pump. The oil explodes and the hot gases push the piston down. As it comes up again, air is blown in and the used gases are pushed out once more.

Diesel engines use a cheaper kind of fuel and give more power for each gallon of fuel burned l than gasoline-engines.

Besides, they last much longer.

In new trains and ships diesel engines run large generators which make electricity. The electricity runs motors which are connected to the wheels of the train or to the ship's screws.

1. for each gallon ['gaelen] of fuel burned – на каждый галлон сжигаемого горючего (1 галлон=4,54 литра; амер=3,78 литра)

2. screw [skru:] – (гребной) винт

Exercises

1. Read the words:

blower, generator, compressed air, diesel, pump, gallon, screw, fuel, injected, immediately, power.

2. Answer the questions:

   1. Whom was a diesel engine named after?

   2. Who was the inventor of a diesel engine?

   3. What is the fuel used in a diesel engine?

   4. What parts does a diesel engine consist of?

   5. What is inside the cylinder in a diesel-engine?

   6. What compresses air till it becomes very hot?

   7. Why does the oil explode immediately in the cylinder?

   8. What types of diesel engines do you know?

   9. What is the advantage of the two stroke engine?

Vocabulary

source - источник

by virtue – при помощи

derive - вырабатывать

engine - двигатель

reciprocating - поршневой

issue - проходить

attain - достигать

deflect - отражать

blade - лопатка

rim - обод

shaft - вал

strike - ударять

movable - подвижный

rotating - вращающий

arrangement - устройство

considerably - значительно

ordinary - обычный

furthermore – более того

respectively - соответственно

perfect - улучшать

record - запись

install - устанавливать

nevertheless – тем не менее

score – записывать (выигрыш)

turn out – выпускать (изделия)

Text

A steam-turbine is like a windmill or a pinwheel. But its metal blades revolve much faster. It is hot steam under great pressure that makes the blades revolve very fast.

To see how the steam-turbine works you can make a model of a steam-turbine as shown in the picture.

As pistons go back and forth in steam-, gasoline- or diesel engines, they must come to a stop before they go the other way. That is why something revolving steadily in one direction makes a better engine. In a steam-turbine the rotor, a shaft with many curved blades, revolves steadily at high speed without stopping.

A revolving wheel makes an excellent engine Windmills and water-wheels are the oldest revolving engines. But such wheels turn slowly and produce little power.

Inside a steam-turbine

The rotor of a steam-turbine may revolve 3,600 times a minute. Steam - tur­bines are mainly used to run huge generators that make electricity.

Questions:

1. What does a steam-turbine look like?

2. What makes an excellent engine?

3. What are the oldest revolving engines?

4. What is the speed of the rotor of a steam-turbine?

5. Why are steam-turbines used?

Perhaps the most widely used source of power in large power plants is the steam turbine. A steam turbine is known to operate by virtue of the heat which it derives from steam and which it converts into mechanical work'. Any apparatus converting heat into mechanical work is considered to be a heat engine. Thus, the steam turbine may also be considered a heat engine. It is different from a reciprocating heat engine, however, in its manner of converting heat into mechanical work.

The fact that steam will issue with considerable velocity through any small opening in a container is, no doubt, known to all. That velocity is derived from heat that the steam liberates on issuing through the opening.

A steam turbine does mechanical work by virtue of the velocity with which steam strikes or leaves its moving parts. The steam attaining its velocity by issuing an opening, its kinetic energy may be converted into mechanical work by suitably deflecting its current.

One modern type of steam turbine is made up of a number of discs with blades set in the rim of the disc, each disc being, fixed to a central shaft. The steam is directed first against the blades of the- first disc and gives up part of its energy to that disc. The steam is deflected by the blades in this case, and then by means of stationary blades it is turned so that it will strike the blades of the next disc. Thus, a series of movable and fixed discs provided with blades, which change the direction of the steam each time it strikes a blade, causes the steam to impart energy to the rotating arrangement several times before its leaving the turbine.

Such steam turbines are considerably more efficient than ordinary reciprocating steam engines. Furthermore, they can be made of very large sizes, capable of producing several hundred thousand kilowatts. The efficiency of a 100,000 kW: steam turbine may be as great as 38% and that of a 200,000 kW turbine-43%, respectively.

It is interesting to note here that the steam turbine was the first form of heat engine developed and the latest to be perfected. Thus, we find it to be the oldest as well as the newest form of heat engine. The earliest record of any heat engine is in a book written by Hero of Alexandria, probably about 150 B. C. (before our era) in which a steam reaction wheel is mentioned. The next development en record was an impulse turbine, and that was in 1629. However, large capacity turbines have been developed only within the last 50 years or so.

Russian steam turbine production started in 1907 when a 200 kW steam turbine was first produced at a Petersburg plant and installed at the power station of that very plant. Nevertheless, the steam turbine was not given due attention in pre-revolutionary Russia.

Great success in the production of powerful steam turbines has been scored by the Soviet industry.

In 1953 our machine builders turned out a super-high-pressure turbine of 150.000 kw capacity. Later years saw the production of the 300.000 kW capacity steam turbine.

The next problem is to master the production of a steam turbine rated at 500,000 and more kilowatts.

Exercises

1. Read the following words:

source, power, turbine, convert, reciprocating, mechanical, through, issue, cause, furthermore, efficiency, engine, development, industry, machine.

2. Answer the following questions:

   1. What is the most widely used source of power in large power plants?

   2. How does a steam turbine operate?

   3. What do you call a heat engine?

   4. Why may a steam turbine be considered a heat engine?

   5. What does a modern type of steam turbine consist of?

   6. When did the Russian steam turbine production start?

   7. When did the large scale turbine construction find its real development in this country?

   8. What is the capacity of modern Soviet turbines?

   9. What kind of turbines is turned out in the Soviet Union?

   10. Where are the steam turbines used?

3. Translate the following sentences:

   1. Locomotives and small stationary steam engines seldom convert into mechanical work as much as 10 per cent of the energy to be developed owing to the burning of fuel.

   2. The steam expanding, its volume is increased.

   3. By reducing the pressure range in each cylinder, a more uniform temperature is maintained in the cylinder itself.

   4. The old reciprocating engine was believed to be the world’s principal source of mechanical work.

   5. Converting heat directly into electricity without using machines is one of the complicated problems.

   6. In sprite of the gases having been compressed, they return to return to their original volume as soon as the applied force has stopped acting.

   7. After reaching the boiling point, the water temperature cannot be increased, in spite of our adding more heat.

   8. To turn a substance from one state to another it is necessary to add or to remove a definite amount of heat.

   9. To tell when an apparatus or a machine is generating a current does not present any difficulty.

   10. We expected the discovery of the plasma to have produced great changes in industry and such was really the case.

4. Retell the article.

Vocabulary

blade - лопатка

curved - вырезанный

reverse - менять

fluid - жидкость

occur - происходить

approach - приближаться

entirely - полностью

bucket - лопатка

revolve - вращаться

definition - определение

circumferential – окружная (скорость)

appreciable - ощутимый

Text

The words "blade" and "vane" are known to be synonyms. Blades or vanes are curved metallic parts of the turbine whose function is to deflect or change the direction of a steam jet. There are both moving blades on which the work of the steam is done and guide blades which reverse the direction of the steam jet so that more work might be derived from it.

Types of turbines. The three fundamental types of steam turbines are 1) impulse, 2) reaction, 3) impulse-and-reaction.

The terms "impulse" and "reaction" have specific meanings in turbine engineering practice, these specific meanings greatly differing from those of the same words as they are used both in physics and in everyday life.

An impulsive force or "impulse" is the force produced on an object when a fluid jet strikes the object.

A well-known characteristic of an impulsive force is that the fluid jet which strikes an object and thereby produces the force leaves the object at the same or at a less velocity than that with which it strikes the object. When the fluid stream strikes an object which is so shaped that it reverses the direction of the stream, a much greater impulsive force is produced than when the direction of the stream is not reversed. This occurs in spite of the fact that the stream may leave the object with the same velocity as that with which it approached the object.

An impulse turbine is such a turbine whose operation almost entirely depends on the impulsive force of a steam jet or jets striking the buckets of the turbine rotor. Hence, an impulse turbine is so designed that the expansion of the steam that passes through it and makes it work occurs almost entirely in its stationary nozzles. Practically no expansion of steam occurs in its moving blades. The steam jet from the stationary nozzles or blades strikes the rotor vanes and thus, causes the rotor to revolve by virtue of the "push" produced.

A reactive force or "reaction" is the force to be produced on an object when a fluid jet leaves the object a greater velocity than that with which the object is approached. The above is a specific turbine engineering definition.

A reaction turbine is the one to depend principally on the reaction force of the steam jets as they leave the turbine's moving blades at greater velocities than those at which they approached the blades. Hence, a reaction turbine is so designed than about half of the steam passing through it and causing it to do work occurs in the moving blades and about half of it in the stationary guide vanes. The guide vanes and moving blades of a reaction turbine are designed in such a manner that the steam flows into the blades without striking them. That is possible provided the circumferential speed of the moving blades is the same as the velocity of the steam stream to enter them. The moving blades are so designed that the steam leaves them at a higher velocity than that at which it enters. Thus, the rotation of the rotor is produced by reaction. The difference between an impulse and a reaction turbine is, therefore, that there appreciable expansion of steam in the moving blades of the first and considerable steam expansion in the moving blades of the second, it follows that in impulse turbines there is practically no difference between the pressure of the steam entering the moving blades and that of the steam leaving them. In reaction turbines there is a difference between these entering and leaving pressures.

An impulse -and-reaction turbine is the one that has some of its blading designed and arranged as in an impulse, turbine and some as in a reaction turbine.

A number of the largest turbines, now in use, are of this type.

Exercises

1. Read the following words:

turbine, reverse, guide, practice, physics, characteristic, impulsive, entirely, design, occur, circumferential, furthermore.

2. Answer the following questions:

   1. What is a vane?

   2. What types of blades are mentioned in the present article?

   3. Do stationary blades reverse the direction of the steam?

   4. What types of turbines do you know?

   5. What is an impulsive force?

   6. What is a well-known characteristic of an impulsive force?

   7. What does the operation an impulse turbine depend upon?

   8. In what manner are the guide vanes and the moving blades of a reaction turbine designed?

   9. What is the difference between an impulse and a reaction turbine?

   10. What types of turbines are in use at present?

3. Translate the following sentences:

   1. It is a well known fact that electrons tend lo flow from the point of lower potential toward that of higher potential.

   2. In any process where heat is transferred the body that is at a lower temperature is the one that gains heat.

   3. The workers know that that invention will help them in the work that they decided to finish ahead of time.

   4. Experiments show that all gases expand on heating.

   5. In impulse turbines we find no difference in the pressure of the steam entering the blades and that of the steam that is leaving them.

   6. The velocity is derived from heat that the steam turbine liberates as it issues through the opening.

   7. That the steam is directed first against the blades of the first disc and gives up part of its energy to that disc is a well known fact.

   8. The steam is deflected by the blades and then by means of stationary blades it is turned so that it will strike the blades of the next disc.

   9. This turbine is more powerful than that one.

   10. That the temperature of an object depends on the average kinetic energy of its molecules is certainly known to you.

4. Describe:

1. an impulse turbine; b. a reaction turbine.

Vocabulary

chamber – камера

blade – лопасть

Text

A gas-turbine is a newer kind, in which the fuel (oil or gas) is burned in a chamber just in front of the turbine blades. The hot high-pressure gases from the burning fuel revolve the blades just as steam does in steam-turbines.

Gas-turbines are smaller than steam-turbines. They run at higher temperatures and at faster speeds.

Inside a gas-turbine

Questions:

1. What fuel is used in a gas-turbine?

2. Where is it burned?

3. What revolves the blades in a gas-turbine?

4. What is the size of gas-turbines?

Vocabulary

atomic pile – ядерный реактор

chemical – химикалий, химический

jet – струя

jet engine (иногда jet) – реактивный двигатель

spray – струя распыленной жидкости

tube – труба, трубка

uranium – уран

Text

A jet engine is a large lube, wider in the middle. Here a spray of oil (which is the fuel used in a jet engine) burns quickly, aided by a blast of air. Hot gases from the burning oil shoot out from the jet engine at high pressure and at great speed.

As the gases go out, the pressure at the back of the jet chamber becomes lower than at the front, and the jet moves towards the high-pressure end. (A toy balloon, full of air, acts like a jet engine. Air, rushing from the balloon's mouth makes it fly forward.)

Jets are very much like rockets. What makes a rocket go forward? More than two hundred years ago-long before there were jet planes-Isaac Newton stated a principle on which we can make a rocket go. He said that for every action there is an equal and opposite reaction. Hotgases shoot out of the back of a rocket, sending it forward, just like a jet. But while a jet needs air to burn its fuel, a rocket does not. A rocket carries oxygen-that part of the air which is needed for things to burn-or a chemical which gives out oxygen.

Rockets use a lot of fuel and burn it very fast. The temperature in the rocket chamber might get so high that ordinary metals would melt. With its own fuel and oxygen a rocket can travel to heights where there is no air.

It is the only type of engine that could take us to the Moon or to Mars.

Questions:

1. How does a jet engine look like?

2. What is the fuel used in a jet engine?

3. What children’s toy acts like a jet engine?

4. What did Isaac Newton say more than two hundred years ago?

5. What does a rocket carry?

6. What is the temperature in the rocket carry?

7. Where can a rocket travel?

8. What is the only type of engine that could take us to other planets?

Vocabulary

atomic pile – ядерный реактор

different – отличный, разный

weight – вес

uranium – уран

a great deal of – много

to blow up – надувать

a balloon – воздушный шар

straight – прямо

to zigzag – делать зигзаги

Text

In all engines fuel is burned to make heat. Then the engine changes this heat into motion. An atomic pile is not an engine and it does not burn anything. It makes heat in a new way. It changes one kind of uranium (Uranium 235) into other chemical substances in such a way that a great deal of heat is released. This change is different from burning. When petrol is burned, the gases that are made weigh more than the petrol. In an atomic pile, the new chemical substances weigh less than the uranium. This little loss in weight means that a little of the uranium has become a great deal of energy. This energy is the heat which can be used to run turbines or other kinds of engines.

Blow up a balloon and let it go. It will jump out of your hand and zigzag around the room. Its direction is always opposite to the flow of air out of the balloon.

If you want to make the balloon go straight, put a paper tube in its mouth and tie it with a string.

Questions:

1. Why is fuel used in all engines?

2. What is the function of an engine?

3. Is an atomic pile an engine?

4. How does an atomic pile make heat?

5. What does it use?

6. Where is an atomic pile used?

7. What can happen if you blow up a balloon and let it go?