The principle of operation of the steam engine

Contents

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1. Theoretical part

1.1 Timeline

1.2 Steam engine

1.2.1 Steam boiler

1.2.2 Steam turbines

1.3 Steam engines

1.3.1 First steamboats

1.3.2 The birth of two-wheelers

1.4 The use of steam engines

1.4.1 Advantage of steam engines

1.4.2 Efficiency

2. Practical part

2.1 Building the mechanism

2.2 Ways to improve the machine and its efficiency

2.3 Questionnaire

Conclusion

Bibliography

Application

steam engineuseful action

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This scientific work consists of 32 sheets. It includes a theoretical part, a practical part, an application and a conclusion. In the theoretical part, you will learn about the principle of operation of steam engines and mechanisms, about their history and the role of their application in life. The practical part details the process of designing and testing the steam mechanism at home. This scientific work can serve as a clear example of the work and use of steam energy.

Introduction

The world of submissive to any vagaries of nature, where machines are driven by muscle power or the power of water wheels and windmills - this was the world of technology before the creation of a steam engine. on fire, is able to displace an obstacle (for example, a sheet of paper) that is in its path. This made a person think about how steam can be used as a working fluid. As a result, after many experiments, a steam engine appeared. And imagine factories with smoking chimneys, steam engines and turbines, steam locomotives and steamships - the whole complex and powerful world of steam engineering created by man. The steam engine was practically the only universal engine and played a huge role in the development of mankind. Invention the steam engine served as an impetus for the further development of vehicles. For a hundred years, it was the only industrial engine, the versatility of which allowed it to be used in factories, railways and navies. The invention of the steam engine is a huge breakthrough, standing at the turn of two eras. And after centuries, the whole significance of this invention is felt even more sharply.

Hypothesis:

Is it possible to build with your own hands the simplest mechanism that worked for a couple.

The purpose of the work: to design a mechanism capable of moving on a pair.

Research objective:

1. Study the scientific literature.

2. Design and build the simplest mechanism that worked on steam.

3. Consider opportunities to increase efficiency in the future.

This scientific work will serve as a manual in physics lessons for high school students and for those who are interested in this topic.

1. TeoRetic part

Steam engine - a thermal piston engine in which the potential energy of water vapor coming from a steam boiler is converted into mechanical work of the reciprocating movement of the piston or rotational movement of the shaft.

Steam is one of the common heat carriers in thermal systems with a heated liquid or gaseous working fluid along with water and thermal oils. Water vapor has a number of advantages, including ease and flexibility of use, low toxicity, and the ability to supply a significant amount of energy to the process. It can be used in a variety of systems that involve direct contact of the coolant with various elements of equipment, effectively contributing to lower energy costs, reducing emissions, and quick payback.

The law of conservation of energy is a fundamental law of nature, established empirically and consisting in the fact that the energy of an isolated (closed) physical system is conserved over time. In other words, energy cannot arise from nothing and cannot disappear into nowhere, it can only pass from one form to another. From a fundamental point of view, according to Noether's theorem, the law of conservation of energy is a consequence of the homogeneity of time and in this sense is universal, that is, inherent in systems of very different physical nature.

1.1 Timeline

4000 BC e. - man invented the wheel.

3000 BC e. - the first roads appeared in ancient Rome.

2000 BC e. - the wheel has become more familiar to us. He had a hub, a rim and spokes connecting them.

1700 BC e. - the first roads paved with wooden blocks appeared.

312 BC e. - The first paved roads were built in ancient Rome. The thickness of the masonry reached one meter.

1405 - the first spring horse-drawn carriages appeared.

1510 - a horse-drawn carriage acquired a body with walls and a roof. Passengers have the opportunity to protect themselves from bad weather during the trip.

1526 - German scientist and artist Albrecht Durer developed an interesting project of a "horseless cart" driven by the muscle power of people. People walking on the side of the carriage rotated special handles. This rotation was transmitted to the wheels of the carriage with the help of a worm gear. Unfortunately, the wagon was not made.

1600 - Simon Stevin built a yacht on wheels, moving under the influence of the force of the wind. She became the first design of a horseless cart.

1610 - carriages underwent two significant improvements. Firstly, the unreliable and too soft belts that rocked passengers during the trip were replaced with steel springs. Secondly, the horse harness was improved. Now the horse pulled the carriage not with its neck, but with its chest.

1649 - passed the first tests on the use of a spring, previously twisted by a person, as a driving force. The spring driven carriage was built by Johann Hauch in Nuremberg. However, historians question this information, since there is a version that instead of a large spring, a person was sitting inside the carriage, who set the mechanism in motion.

1680 - the first samples of horse-drawn public transport appeared in large cities.

1690 - Stefan Farffler from Nuremberg created a three-wheeled cart that moves with the help of two handles rotated by hands. Thanks to this drive, the wagon designer could move from place to place without the help of his legs.

1698 - Englishman Thomas Savery built the first steam boiler.

1741 - Russian self-taught mechanic Leonty Lukyanovich Shamshurenkov sent a “report” describing a “self-running carriage” to the Nizhny Novgorod provincial office.

1769 - French inventor Cugno built the world's first steam car.

1784 - James Watt builds the first steam engine.

1791 - Ivan Kulibin designed a three-wheeled self-propelled carriage that could accommodate two passengers. The drive was carried out using a pedal mechanism.

1794 - Cugno's steam engine was handed over to the "repository of machines, tools, models, drawings and descriptions of all kinds of arts and crafts" as another mechanical curiosity.

1800 - there is an opinion that it was in this year that the world's first bicycle was built in Russia. Its author was the serf Yefim Artamonov.

1808 - The first French bicycle appeared on the streets of Paris. It was made of wood and consisted of a crossbar connecting two wheels. Unlike the modern bicycle, it had no handlebars or pedals.

1810 - the carriage industry began to emerge in America and European countries. In large cities, entire streets and even quarters populated by master coachmakers appeared.

1816 - German inventor Carl Friedrich Dreis built a machine resembling a modern bicycle. As soon as it appeared on the streets of the city, it received the name "running car", since its owner, pushing off with his feet, actually ran along the ground.

1834 - a sailing crew designed by M. Hakuet was tested in Paris. This crew had a mast 12 m high.

1868 - It is believed that this year the Frenchman Erne Michaud created the prototype of the modern motorcycle.

1871 - French inventor Louis Perrault developed a bicycle steam engine.

1874 - a steam wheeled tractor was built in Russia. The English car "Evelyn Porter" was used as a prototype.

1875 - Amadeus Bdlly's first steam engine was demonstrated in Paris.

1884 - American Louis Copland built a motorcycle on which a steam engine was mounted above the front wheel. This design could accelerate to 18 km / h.

1901 - in Russia, a passenger steam car of the Moscow bicycle plant "Duks" was built.

1902 - Leon Serpollet on one of his steam cars set a world speed record - 120 km / h.

A year later, he set another record - 144 km / h.

1905 - American F. Marriott on a steam car exceeded the speed of 200 km

1.2 Steamengine

An engine powered by steam. The steam produced by heating water is used for propulsion. In some engines, the steam forces the pistons in the cylinders to move. This creates a reciprocating motion. The connected mechanism usually converts it into rotational motion. Steam locomotives (locomotives) use reciprocating engines. Steam turbines are also used as engines, which give direct rotational motion by rotating a series of wheels with blades. Steam turbines drive power generators and ship propellers. In any steam engine, the heat generated by heating water in a steam boiler (boiler) is converted into motion energy. Heat can be supplied from burning fuel in a furnace or from a nuclear reactor. The very first steam engine in history was a kind of pump, with the help of which they pumped out the water flooding the mines. It was invented in 1689 by Thomas Savery. In this machine, very simple in design, the steam condensed into a small amount of water, and due to this, a partial vacuum was created, due to which water was sucked out of the mine shaft. In 1712, Thomas Newcomen invented the steam-powered piston pump. In the 1760s James Watt improved Newcomen's design and created much more efficient steam engines. Soon they were used in factories to power machine tools. In 1884, English engineer Charles Parson (1854-1931) invented the first practical steam turbine. His designs were so efficient that they soon began to replace reciprocating steam engines in power plants. The most amazing achievement in the field of steam engines was the creation of a completely closed, working steam engine of microscopic dimensions. Japanese scientists created it using techniques used to make integrated circuits. A small current passing through the electric heating element turns the drop of water into steam, which moves the piston. Now scientists have to discover in which areas this device can find practical applications.

Interest in water vapor, as an affordable source of energy, appeared along with the first scientific knowledge of the ancients. People have been trying to tame this energy for three millennia. What are the main stages of this path? Whose reflections and projects have taught mankind to extract the maximum benefit from it?

Prerequisites for the emergence of steam engines

The need for mechanisms that can facilitate labor-intensive processes has always existed. Until about the middle of the 18th century, windmills and water wheels were used for this purpose. The possibility of using wind energy directly depends on the vagaries of the weather. And to use water wheels, factories had to be built along the banks of rivers, which is not always convenient and expedient. And the effectiveness of both was extremely low. A fundamentally new engine was needed, easily managed and devoid of these shortcomings.

The history of the invention and improvement of steam engines

The creation of a steam engine is the result of much thought, success and failure of the hopes of many scientists.

The beginning of the way

The first, single projects were only interesting curiosities. For example, Archimedes built a steam gun Heron of Alexandria used the energy of steam to open the doors of ancient temples. And researchers find notes on the practical application of steam energy to actuate other mechanisms in the works Leonardo da Vinci.

Consider the most significant projects on this topic.

In the 16th century, the Arab engineer Tagi al Din developed a design for a primitive steam turbine. However, it did not receive practical application due to the strong dispersion of the steam jet supplied to the turbine wheel blades.

Fast forward to medieval France. The physicist and talented inventor Denis Papin, after many unsuccessful projects, stops at the following design: a vertical cylinder was filled with water, over which a piston was installed.

The cylinder was heated, the water boiled and evaporated. The expanding steam lifted the piston. It was fixed at the top point of the rise and the cylinder was expected to cool and the steam to condense. After the steam condensed, a vacuum was formed in the cylinder. The piston, freed from fastening, rushed into vacuum under the action of atmospheric pressure. It was this fall of the piston that was supposed to be used as a working stroke.

So, the useful stroke of the piston was caused by the formation of a vacuum due to the condensation of steam and external (atmospheric) pressure.

Because the Papin steam engine like most subsequent projects, they were called steam-atmospheric machines.

This design had a very significant drawback - the repeatability of the cycle was not provided. Denis comes up with the idea of ​​getting steam not in a cylinder, but separately in a steam boiler.

Denis Papin entered the history of the creation of steam engines as the inventor of a very important detail - the steam boiler.

And since they began to receive steam outside the cylinder, the engine itself passed into the category of external combustion engines. But due to the lack of a distribution mechanism that ensures uninterrupted operation, these projects have hardly found practical application.

A new stage in the development of steam engines

For about 50 years, it has been used to pump water in coal mines. Thomas Newcomen's steam pump. He largely repeated the previous designs, but contained very important novelties - a pipe for the withdrawal of condensed steam and a safety valve for the release of excess steam.

Its significant drawback was that the cylinder had to be heated before steam was injected, then cooled before it condensed. But the need for such engines was so high that, despite their obvious inefficiency, the last copies of these machines served until 1930.

In 1765 English mechanic James Watt, engaged in the improvement of Newcomen's machine, separated the condenser from the steam cylinder.

It became possible to keep the cylinder constantly heated. The efficiency of the machine immediately increased. In subsequent years, Watt significantly improved his model, equipping it with a device for supplying steam from one side to the other.

It became possible to use this machine not only as a pump, but also to drive various machine tools. Watt received a patent for his invention - a continuous steam engine. The mass production of these machines begins.

By the beginning of the 19th century, over 320 Watt steam engines were operating in England. Other European countries also began to buy them. This contributed to a significant increase in industrial production in many industries, both in England itself and in neighboring states.

Twenty years earlier than Watt, in Russia, the Altai mechanic Ivan Ivanovich Polzunov worked on the steam engine project.

The factory authorities suggested that he build a unit that would drive the blower of the melting furnace.

The machine he built was a two-cylinder and ensured the continuous operation of the device connected to it.

Having successfully worked for more than a month and a half, the boiler started leaking. Polzunov himself was no longer alive by this time. The car was not repaired. And the wonderful creation of a single Russian inventor was forgotten.

Due to the backwardness of Russia at that time the world learned about the invention of I. I. Polzunov with a great delay ....

So, to drive a steam engine, it is necessary that the steam generated by the steam boiler, expanding, presses on the piston or on the turbine blades. And then their movement was transferred to other mechanical parts.

The use of steam engines in transport

Despite the fact that the efficiency of steam engines of that time did not exceed 5%, by the end of the 18th century they began to be actively used in agriculture and transport:

• in France there is a car with a steam engine;
• in the USA, a steamboat begins to run between the cities of Philadelphia and Burlington;
• in England, a steam-powered railway locomotive was demonstrated;
• a Russian peasant from the Saratov province patented a caterpillar tractor built by him with a capacity of 20 hp. With.;
• attempts have been repeatedly made to build an aircraft with a steam engine, but, unfortunately, the low power of these units with the large weight of the aircraft made these attempts unsuccessful.

By the end of the 19th century, steam engines, having played their role in the technical progress of society, gave way to electric motors.

Steam devices in the XXI century

With the advent of new energy sources in the 20th and 21st centuries, the need to use steam energy appears again. Steam turbines are becoming an integral part of nuclear power plants. The steam that powers them is obtained from nuclear fuel.

These turbines are also widely used in condensing thermal power plants.

In a number of countries, experiments are being carried out to obtain steam due to solar energy.

Reciprocating steam engines are not forgotten either. In mountainous areas as a locomotive steam locomotives are still used.

These reliable workers are both safer and cheaper. They do not need power lines, and fuel - wood and cheap grades of coal - are always at hand.

Modern technologies allow capturing up to 95% of emissions into the atmosphere and increasing efficiency up to 21%, so that people have decided not to part with them yet and are working on a new generation of steam locomotives.

If this message was useful to you, I would be glad to see you

I live on coal and water and still have enough energy to go 100 miles an hour! This is exactly what a steam locomotive can do. Although these giant mechanical dinosaurs are now extinct on most of the world's railroads, steam technology lives on in people's hearts, and locomotives like this one still serve as tourist attractions on many historic railroads.

The first modern steam engines were invented in England in the early 18th century and marked the beginning of the Industrial Revolution.

Today we are returning to steam energy again. Due to the design features, during the combustion process, a steam engine produces less pollution than an internal combustion engine. Watch this video to see how it works.

What powered the old steam engine?

It takes energy to do absolutely anything you can think of: skateboarding, flying a plane, shopping or driving down the street. Most of the energy we use for transportation today comes from oil, but that wasn't always the case. Until the early 20th century, coal was the world's favorite fuel, and it powered everything from trains and ships to the ill-fated steam aircraft invented by American scientist Samuel P. Langley, an early competitor of the Wright brothers. What is so special about coal? There is plenty of it inside the Earth, so it was relatively inexpensive and widely available.

Coal is an organic chemical, which means it is based on the element carbon. Coal is formed over millions of years when the remains of dead plants are buried under rocks, compressed under pressure and boiled by the internal heat of the Earth. That's why it's called fossil fuel. Lumps of coal are really lumps of energy. The carbon inside them is bonded to hydrogen and oxygen atoms by compounds called chemical bonds. When we burn coal on fire, the bonds break and energy is released in the form of heat.

Coal contains about half as much energy per kilogram as cleaner fossil fuels like gasoline, diesel and kerosene – and that's one reason steam engines have to burn so much.

Are steam engines ready for an epic comeback?

Once upon a time, the steam engine dominated - first in trains and heavy tractors, as you know, but eventually in cars. It's hard to understand today, but at the turn of the 20th century, more than half of the cars in the US were powered by steam. The steam engine was so improved that in 1906 a steam engine called the Stanley Rocket even held the land speed record - a reckless speed of 127 miles per hour!

Now, you might think that the steam engine was only successful because internal combustion engines (ICE) didn't exist yet, but in fact, steam engines and ICE cars were developed at the same time. Because the engineers already had 100 years of experience with steam engines, the steam engine had a pretty big head start. While manual crank engines broke the hands of unfortunate operators, by 1900 steam engines were already fully automated - and without a clutch or gearbox (steam provides constant pressure, unlike the stroke of an internal combustion engine), very easy to operate. The only caveat is that you had to wait a few minutes for the boiler to heat up.

However, in a few short years, Henry Ford will come along and change everything. Although the steam engine was technically superior to the internal combustion engine, it could not match the price of production Fords. Steam car manufacturers tried to shift gears and sell their cars as premium, luxury products, but by 1918 the Ford Model T was six times cheaper than the Steanley Steamer (the most popular steam car at the time). With the advent of the electric starter motor in 1912 and the constant improvement in the efficiency of the internal combustion engine, it was not long before the steam engine disappeared from our roads.

Under pressure

For the past 90 years, steam engines have remained on the verge of extinction, and giant beasts have rolled out to vintage car shows, but not by much. Quietly, however, in the background, research has quietly moved forward, partly because of our reliance on steam turbines for power generation, and also because some people believe that steam engines can actually outperform internal combustion engines.

ICEs have intrinsic disadvantages: they require fossil fuels, they produce a lot of pollution, and they are noisy. Steam engines, on the other hand, are very quiet, very clean, and can use almost any fuel. Steam engines, thanks to constant pressure, do not require gearing - you get maximum torque and acceleration instantly, at rest. For city driving, where stopping and starting consumes huge amounts of fossil fuels, the continuous power of steam engines can be very interesting.

Technology has come a long way and since the 1920s - first of all, we are now material masters. The original steam engines required huge, heavy boilers to withstand the heat and pressure, and as a result, even small steam engines weighed a couple of tons. With modern materials, steam engines can be as light as their cousins. Throw in a modern condenser and some sort of evaporating boiler and you can build a steam engine with decent efficiency and warm-up times that are measured in seconds rather than minutes.

In recent years, these achievements have combined into some exciting developments. In 2009, a British team set a new steam-powered wind speed record of 148 mph, finally breaking the Stanley rocket record that had stood for over 100 years. In the 1990s, a Volkswagen R&D division called Enginion claimed that it had built a steam engine that was comparable in efficiency to an internal combustion engine, but with lower emissions. In recent years, Cyclone Technologies claims to have developed a steam engine that is twice as efficient as an internal combustion engine. To date, however, no engine has found its way into a commercial vehicle.

Moving forward, it's unlikely that steam engines will ever get off the internal combustion engine, if only because of Big Oil's huge momentum. However, one day, when we finally decide to take a serious look at the future of personal transportation, perhaps the quiet, green, gliding grace of steam energy will get a second chance.

Steam engines of our time

Technology.

innovative energy. NanoFlowcell® is currently the most innovative and most powerful energy storage system for mobile and stationary applications. Unlike conventional batteries, the nanoFlowcell® is powered by liquid electrolytes (bi-ION) that can be stored away from the cell itself. The exhaust of a car with this technology is water vapour.

Like a conventional flow cell, the positively and negatively charged electrolytic fluids are stored separately in two reservoirs and, like a conventional flow cell or fuel cell, are pumped through the transducer (the actual element of the nanoFlowcell system) in separate circuits.

Here, the two electrolyte circuits are separated only by a permeable membrane. Ion exchange occurs as soon as the positive and negative electrolyte solutions pass through each other on both sides of the converter membrane. This converts the chemical energy bound into the bi-ion into electricity, which is then directly available to electricity consumers.

Like hydrogen vehicles, the "exhaust" produced by nanoFlowcell electric vehicles is water vapour. But are water vapor emissions from future electric vehicles environmentally friendly?

Critics of electric mobility are increasingly questioning the environmental compatibility and sustainability of alternative energy sources. For many, electric vehicles are a mediocre compromise between zero-emission driving and environmentally harmful technology. Ordinary lithium-ion or metal hydride batteries are neither sustainable nor environmentally friendly - not to be manufactured, used or recycled, even if the advertising suggests pure "e-mobility".

nanoFlowcell Holdings is also frequently asked about the sustainability and environmental compatibility of nanoFlowcell technology and bi-ionic electrolytes. Both the nanoFlowcell itself and the bi-ION electrolyte solutions required to power it are produced in an environmentally friendly way from environmentally friendly raw materials. During operation, nanoFlowcell technology is completely non-toxic and does not harm health in any way. Bi-ION, which consists of a low-salt aqueous solution (organic and mineral salts dissolved in water) and actual energy carriers (electrolytes), is also environmentally friendly when used and recycled.

How does the nanoFlowcell drive work in an electric car? Similar to a gasoline car, the electrolyte solution is consumed in an electric vehicle with a nanoflowcell. Inside the nanoarm (actual flow cell), one positively and one negatively charged electrolyte solution is pumped across the cell membrane. The reaction - ion exchange - takes place between positively and negatively charged electrolyte solutions. Thus, the chemical energy contained in the bi-ions is released in the form of electricity, which is then used to drive electric motors. This happens as long as the electrolytes are pumped across the membrane and react. In the case of a QUANTiNO drive with nanoflowcell, one reservoir of electrolyte liquid is sufficient for more than 1000 kilometers. After emptying the tank must be refilled.

What kind of "waste" is generated by an electric vehicle with nanoflowcell? In a conventional internal combustion engine vehicle, the combustion of fossil fuels (gasoline or diesel) produces hazardous exhaust gases - mainly carbon dioxide, nitrogen oxides and sulfur dioxide - the accumulation of which has been identified by many researchers as the cause of climate change. change. However, the only emissions emitted by the nanoFlowcell vehicle while driving are - almost like a hydrogen-powered vehicle - almost entirely water.

After the ion exchange took place in the nanocell, the chemical composition of the bi-ION electrolyte solution remained virtually unchanged. It is no longer reactive and is thus considered "spent" as it cannot be recharged. Therefore, for mobile applications of nanoFlowcell technology, such as electric vehicles, the decision was made to microscopically vaporize and release the dissolved electrolyte while the vehicle is in motion. At speeds above 80 km/h, the waste electrolytic fluid container is emptied through extremely fine spray nozzles using a generator driven by drive energy. Electrolytes and salts are pre-filtered mechanically. The release of currently purified water in the form of cold water vapor (microfine mist) is fully compatible with the environment. The filter is changed at about 10 g.

The advantage of this technical solution is that the tank of the vehicle is emptied during normal driving and can be easily and quickly replenished without the need for pumping.

An alternative solution, which is somewhat more complex, is to collect the spent electrolyte solution in a separate tank and send it for recycling. This solution is intended for similar stationary nanoFlowcell applications.

However, many critics now suggest that the type of water vapor that is released from hydrogen conversion in fuel cells, or from the evaporation of electrolytic fluid in the case of a nanotubing, is theoretically a greenhouse gas that could have an impact on climate change. How do such rumors arise?

We look at water vapor emissions in terms of their environmental significance and ask how much more water vapor can be expected from the widespread use of nanoflowcell vehicles compared to traditional drive technologies and whether these H 2 O emissions could have negative environmental impacts. Wednesday.

The most important natural greenhouse gases - along with CH 4 , O 3 and N 2 O - water vapor and CO 2 , carbon dioxide and water vapor are incredibly important for maintaining the global climate. Solar radiation that reaches the earth is absorbed and warms the earth, which in turn radiates heat to the atmosphere. However, most of this radiated heat escapes back into space from the Earth's atmosphere. Carbon dioxide and water vapor have the properties of greenhouse gases, forming a "protective layer" that prevents all radiant heat from escaping back into space. In a natural context, this greenhouse effect is critical to our survival on Earth—without carbon dioxide and water vapor, Earth's atmosphere would be hostile to life.

The greenhouse effect only becomes problematic when unpredictable human intervention disrupts the natural cycle. When, in addition to natural greenhouse gases, humans cause a higher concentration of greenhouse gases in the atmosphere by burning fossil fuels, this increases the heating of the Earth's atmosphere.

As part of the biosphere, humans inevitably affect the environment, and hence the climate system, by their very existence. The constant growth of the Earth's population after the Stone Age and the establishment of settlements several thousand years ago, associated with the transition from nomadic life to agriculture and animal husbandry, has already affected the climate. Nearly half of the world's original forests and forests have been cleared for agricultural purposes. Forests - along with oceans - are the main producer of water vapor.

Water vapor is the main absorber of thermal radiation in the atmosphere. Water vapor averages 0.3% by mass of the atmosphere, carbon dioxide only 0.038%, which means that water vapor makes up 80% of the mass of greenhouse gases in the atmosphere (about 90% by volume) and, taking into account from 36 to 66% is the most important greenhouse gas that ensures our existence on earth.

Table 3: Atmospheric share of the most important greenhouse gases and absolute and relative share of temperature increase (Zittel)

A steam engine is a heat engine in which the potential energy of expanding steam is converted into mechanical energy given to the consumer.

We will get acquainted with the principle of operation of the machine using the simplified diagram of Fig. 1.

Inside cylinder 2 is a piston 10 which can move back and forth under steam pressure; the cylinder has four channels that can be opened and closed. Two upper steam channels1 And3 are connected by a pipeline to the steam boiler, and through them fresh steam can enter the cylinder. Through the two lower capals 9 and 11, the pair, which has already completed the work, is released from the cylinder.

The diagram shows the moment when channels 1 and 9 are open, channels 3 and11 closed. Therefore, fresh steam from the boiler through the channel1 enters the left cavity of the cylinder and, with its pressure, moves the piston to the right; at this time, the exhaust steam is removed from the right cavity of the cylinder through channel 9. With the extreme right position of the piston, the channels1 And9 are closed, and 3 for the inlet of fresh steam and 11 for the exhaust of exhaust steam are open, as a result of which the piston will move to the left. At the extreme left position of the piston, channels open1 and 9 and channels 3 and 11 are closed and the process is repeated. Thus, a rectilinear reciprocating motion of the piston is created.

To convert this movement into rotational, the so-called crank mechanism is used. It consists of a piston rod - 4, connected at one end to the piston, and at the other, pivotally, by means of a slider (crosshead) 5, sliding between the guide parallels, with a connecting rod 6, which transmits movement to the main shaft 7 through its knee or crank 8.

The amount of torque on the main shaft is not constant. Indeed, the strengthR , directed along the stem (Fig. 2), can be decomposed into two components:TO directed along the connecting rod, andN , perpendicular to the plane of the guide parallels. The force N has no effect on the movement, but only presses the slider against the guide parallels. ForceTO is transmitted along the connecting rod and acts on the crank. Here it can again be decomposed into two components: the forceZ , directed along the radius of the crank and pressing the shaft against the bearings, and the forceT perpendicular to the crank and causing the shaft to rotate. The magnitude of the force T will be determined from the consideration of the triangle AKZ. Since the angle ZAK = ? + ?, then

T = K sin (? + ?).

But from the OCD triangle the strength

K= P/ cos ?

That's why

T= psin( ? + ?) / cos ? ,

During the operation of the machine for one revolution of the shaft, the angles? And? and strengthR are continuously changing, and therefore the magnitude of the torsional (tangential) forceT also variable. To create a uniform rotation of the main shaft during one revolution, a heavy flywheel is mounted on it, due to the inertia of which a constant angular speed of rotation of the shaft is maintained. In those moments when the powerT increases, it cannot immediately increase the speed of rotation of the shaft until the flywheel accelerates, which does not happen instantly, since the flywheel has a large mass. At those moments when the work produced by the twisting forceT , the work of the resistance forces created by the consumer becomes less, the flywheel, again, due to its inertia, cannot immediately reduce its speed and, giving off the energy received during its acceleration, helps the piston overcome the load.

At the extreme positions of the piston angles? +? = 0, so sin (? + ?) = 0 and, therefore, T = 0. Since there is no rotational force in these positions, if the machine were without a flywheel, sleep would have to stop. These extreme positions of the piston are called dead positions or dead points. The crank also passes through them due to the inertia of the flywheel.

In dead positions, the piston is not brought into contact with the cylinder covers, a so-called harmful space remains between the piston and the cover. The volume of harmful space also includes the volume of steam channels from the steam distribution organs to the cylinder.

StrokeS called the path traveled by the piston when moving from one extreme position to another. If the distance from the center of the main shaft to the center of the crank pin - the radius of the crank - is denoted by R, then S = 2R.

Cylinder displacement V h called the volume described by the piston.

Typically, steam engines are double (double-sided) action (see Fig. 1). Sometimes single-acting machines are used, in which steam exerts pressure on the piston only from the side of the cover; the other side of the cylinder in such machines remains open.

Depending on the pressure with which the steam leaves the cylinder, the machines are divided into exhaust, if the steam escapes into the atmosphere, condensing, if the steam enters the condenser (a refrigerator where reduced pressure is maintained), and heat extraction, in which the steam exhausted in the machine is used for any purpose (heating, drying, etc.)

The process of inventing a steam engine, as is often the case in technology, stretched out for almost a century, so the choice of a date for this event is rather arbitrary. However, no one denies that the breakthrough that led to the technological revolution was carried out by the Scot James Watt.

People have thought about using steam as a working fluid since ancient times. However, only at the turn of the XVII-XVIII centuries. managed to find a way to produce useful work with the help of steam. One of the first attempts to put steam at the service of man was made in England in 1698: the inventor Savery's machine was designed to drain mines and pump water. True, Savery's invention was not yet an engine in the full sense of the word, since, apart from a few manually opened and closed valves, it had no moving parts. Savery's machine worked as follows: first, a sealed tank was filled with steam, then the outer surface of the tank was cooled with cold water, causing the steam to condense, and a partial vacuum was created in the tank. After that, water - for example, from the bottom of the mine - was sucked into the tank through the intake pipe and, after the next portion of steam was admitted, was thrown out.

The first steam engine with a piston was built by the Frenchman Denis Papin in 1698. Water was heated inside a vertical cylinder with a piston, and the resulting steam pushed the piston up. As the steam cooled and condensed, the piston was pushed down by atmospheric pressure. Through a system of blocks, Papin's steam engine could drive various mechanisms, such as pumps.

A more perfect machine was built in 1712 by the English blacksmith Thomas Newcomen. As in Papin's machine, the piston moved in a vertical cylinder. Steam from the boiler entered the base of the cylinder and lifted the piston up. When cold water was injected into the cylinder, the steam condensed, a vacuum formed in the cylinder, and under the influence of atmospheric pressure the piston fell down. This return stroke removed the water from the cylinder and, by means of a chain connected to a rocker, moving like a swing, raised the pump rod upwards. When the piston was at the bottom of its stroke, steam again entered the cylinder, and with the help of a counterweight mounted on the pump rod or on the rocker, the piston rose to its original position. After that, the cycle was repeated.

The Newcomen machine was widely used in Europe for over 50 years. In the 1740s, a machine with a cylinder 2.74 m long and 76 cm in diameter did in one day the work that a team of 25 people and 10 horses, working in shifts, did in a week. And yet its efficiency was extremely low.

The most striking industrial revolution manifested itself in England, primarily in the textile industry. The discrepancy between the supply of fabrics and the rapidly increasing demand attracted the best design minds to the development of spinning and weaving machines. The history of English technology forever included the names of Cartwright, Kay, Crompton, Hargreaves. But the spinning and weaving machines they created needed a qualitatively new, universal engine that would continuously and evenly (which the water wheel could not provide) would drive the machines into unidirectional rotational motion. It was here that the talent of the famous engineer, the "wizard of Greenock" James Watt, appeared in all its splendor.

Watt was born in the Scottish town of Greenock in the family of a shipbuilder. Working as an apprentice in workshops in Glasgow, in the first two years, James acquired the qualifications of an engraver, a master in the manufacture of mathematical, surveying, optical instruments, and various navigational instruments. On the advice of his uncle, the professor, James entered the local university as a mechanic. It was here that Watt began working on steam engines.

James Watt was trying to improve Newcomen's steam-atmospheric machine, which, in general, was only good for pumping water. It was clear to him that the main drawback of Newcomen's machine was the alternating heating and cooling of the cylinder. In 1765, Watt came up with the idea that the cylinder could remain hot all the time if, before condensation, the steam was diverted into a separate reservoir through a pipeline with a valve. In addition, Watt made several more improvements that finally turned the steam-atmospheric engine into a steam engine. For example, he invented a hinged mechanism - "Watt's parallelogram" (so called because part of the links - the levers that make up its composition forms a parallelogram), which converted the reciprocating movement of the piston into the rotational movement of the main shaft. Now the looms could run continuously.

In 1776 Watt's machine was tested. Its efficiency turned out to be twice that of Newcomen's machine. In 1782, Watt created the first universal double-acting steam engine. Steam entered the cylinder alternately from one side of the piston, then from the other. Therefore, the piston made both a working and a reverse stroke with the help of steam, which was not the case in previous machines. Since the piston rod in a double-acting steam engine performed a pulling and pushing action, the old drive system of chains and rocker arms, which responded only to traction, had to be redone. Watt developed a linkage system and used a planetary mechanism to convert the reciprocating motion of a piston rod into rotational motion, using a heavy flywheel, a centrifugal speed controller, a disk valve, and a manometer to measure steam pressure. The “rotary steam engine” patented by Watt was first widely used in spinning and weaving mills, and later in other industrial enterprises. The Watt engine was suitable for any car, and the inventors of self-propelled mechanisms were not slow to take advantage of this.

Watt's steam engine was truly the invention of the century, marking the beginning of the industrial revolution. But the inventor did not stop there. Neighbors watched with surprise more than once as Watt drove horses across the meadow, pulling specially selected weights. So there was a unit of power - horsepower, which later received universal recognition.

Unfortunately, financial difficulties forced Watt, already in adulthood, to carry out geodetic surveys, work on the construction of canals, build ports and marinas, and finally enter into an economically enslaving alliance with entrepreneur John Rebeck, who soon suffered a complete financial collapse.