From the history of the steam turbine. The miracle of engineering or the history of the invention of turbines

Laval's reversible turbine The development of steam turbines as marine engines was entirely due to the persistent, persistent and long-term activity of Parsons. Already in 1894, Parsons, after long and careful experiments, managed to design turbines,

TURBINA Nika TURBINA Nika (poetess; committed suicide (thrown out of the window) on May 11, 2002 at the age of 28; buried at the Vagankovsky cemetery in Moscow). The turbine became famous in the mid-80s, when her poems began to be published in all Soviet media. Nika at 12

With Pierre Laval Solzhenitsyn's behavior and political concepts are surprisingly similar to the behavior and views of Pierre Laval, a traitor to the French people. Both, in the name of "deliverance" from the "evil" existing in the state, stood up for the defeat of the nation. Both of them are apologists

The invention of steam turbines.

Along with the hydraulic turbines described in one of the previous chapters, the invention and distribution of steam turbines was of great importance for energy and electrification. The principle of their operation was similar to hydraulic ones, with the difference, however, that the hydraulic turbine was driven by a jet of water, and the steam turbine was driven by a jet of heated steam. In the same way that the water turbine represented a new word in the history of water engines, the steam engine demonstrated the new possibilities of the steam engine.

The old Watt machine, which celebrated its centenary in the third quarter of the 19th century, had a low efficiency, since the rotational movement was obtained in it in a complex and irrational way. In fact, as we remember, the steam did not move the rotating wheel itself here, but put pressure on the piston, from the piston through the rod, connecting rod and crank, the movement was transmitted to the main shaft. As a result of numerous transfers and transformations, a huge part of the energy received from the combustion of fuel, in the full sense of the word, flew out into the pipe without any benefit. More than once, inventors tried to design a simpler and more economical machine - a steam turbine, in which a steam jet would directly rotate the impeller. A simple calculation showed that it should have an efficiency several orders of magnitude higher than Watt's machine. However, there were many obstacles in the way of engineering thought. In order for a turbine to truly become a highly efficient engine, the impeller had to rotate at a very high speed, making hundreds of revolutions per minute. For a long time this could not be achieved, because they did not know how to give the proper speed to the steam jet.

The first important step in the development of a new technical tool that replaced the steam engine was made by the Swedish engineer Carl Gustav Patrick Laval in 1889. The Laval steam turbine is a wheel with blades. A jet of water formed in the boiler breaks out of the pipe (nozzle), presses on the blades and spins the wheel. Experimenting with different steam day pipes, the designer came to the conclusion that they should be in the shape of a cone. This is how the Laval nozzle, which has been used up to our time, appeared.

It was not until 1883 that the Swede Gustav Laval managed to overcome many difficulties and create the first working steam turbine. A few years earlier, Laval had obtained a patent for a milk separator. In order to put it into action, a very high-speed drive was needed. None of the then existing engines did not satisfy the task. Laval was convinced that only a steam turbine could give him the necessary rotational speed. He began to work on its design and eventually achieved what he wanted. The Laval turbine was a light wheel, on the blades of which steam was induced through several nozzles set at an acute angle. In 1889, Laval significantly improved his invention by adding conical expanders to the nozzles. This significantly increased the efficiency of the hydroturbine and turned it into a universal engine.

The principle of operation of the turbine was extremely simple. Steam, heated to a high temperature, came from the boiler through the steam pipe to the nozzles and burst out. In the nozzles, the steam expanded to atmospheric pressure. Due to the increase in volume accompanying this expansion, a significant increase in the outflow rate was obtained (when expanding from 5 to 1 atmosphere, the speed of the steam jet reached 770 m/s). Thus, the energy contained in the steam was transferred to the turbine blades. The number of nozzles and steam pressure determined the power of the turbine. When the exhaust steam was not released directly into the air, but was sent, as in steam engines, to a condenser and liquefied at reduced pressure, the power of the turbine was the highest. Thus, when the steam expands from 5 atmospheres to 1/10 of an atmosphere, the jet velocity reaches a supersonic value.

Despite its apparent simplicity, the Laval turbine was a real marvel of engineering. It is enough to imagine the loads that the impeller experienced in it to understand how difficult it was for the inventor to achieve uninterrupted operation from his offspring. At huge speeds of the turbine wheel, even a slight shift in the center of gravity caused a strong load on the axle and overload of the bearings. To avoid this, Laval came up with the idea of ​​putting the wheel on a very thin axle, which, when rotated, could bend slightly. When untwisted, it itself came to a strictly central position, which was then held at any speed of rotation. Thanks to this ingenious solution, the destructive effect on the bearings was reduced to a minimum.

As soon as it appeared, the Laval turbine won universal recognition. It was much more economical than the old steam engines, very easy to handle, took up little space, and was easy to install and connect. The Laval turbine gave especially great benefits when it was connected to high-speed machines: saws, separators, centrifugal pumps. It was also successfully used as a drive for an electric generator, but nevertheless, for it, it had an excessive great speed and therefore could only act through a gearbox (a system of gears that lowered the speed of rotation when transferring movement from the turbine shaft to the generator shaft).

In 1884, the English engineer Parson received a patent for a multi-stage jet turbine, which he invented specifically to drive an electric generator. In 1885, he designed a multi-stage jet turbine, which later became widely used in thermal power plants. She had the following device, reminiscent of a jet turbine device. A row of rotating wheels with blades was mounted on the central shaft. Between these wheels were fixed rims (discs) with blades that had the opposite direction. Steam under high pressure was supplied to one of the ends of the turbine. The pressure at the other end was small (less than atmospheric). Therefore, the steam sought to pass through the turbine. First, he acted in the gaps between the shoulder blades of the first crown. These blades directed it to the blades of the first movable wheel. Steam passed between them, causing the wheels to turn. Then he entered the second crown. The blades of the second crown directed steam between the blades of the second movable wheel, which also came into rotation. From the second movable wheel, steam flowed between the blades of the third crown, and so on. All blades were given such a shape that the cross section of the interblade channels decreased in the direction of steam flow. The blades, as it were, formed nozzles mounted on the shaft, from which, expanding, steam flowed out. Both active and reactive power were used here. Rotating, all the wheels rotated the turbine shaft. Outside, the device was enclosed in a strong casing. In 1889, about three hundred of these turbines were already used to generate electricity, and in 1899 the first power station with Parson steam turbines was built in Elberfeld. Meanwhile, Parson tried to expand the scope of his invention. In 1894, he built an experimental vessel "Turbinia" driven by a steam turbine. On tests, it demonstrated a record speed of 60 km / h. After that, steam turbines began to be installed on many high-speed ships.

A steam turbine plant is a continuously operating thermal unit, the working medium of which is water and steam. A steam turbine is a power engine in which the potential energy of the steam is converted into kinetic energy, and the kinetic energy, in turn, is converted into mechanical energy of the rotor rotation. The turbine rotor is connected directly or by means of a gear to the working machine. Depending on the purpose of the working machine, a steam turbine can be used in a wide variety of industries: in energy, in transport, in sea and river navigation, etc. Includes steam turbine and auxiliary equipment.

History of the steam turbine

The operation of a steam turbine is based on two principles of creating a circumferential force on the rotor, known since ancient times - reactive and active. Back in 130 BC. Hero of Alexandria invented a device called the aeolipil. In accordance with Figure 2.1, it was a hollow sphere filled with steam with two L-shaped nozzles located on opposite sides and directed in different directions. Steam flowed out of the nozzles at high speed, and due to the resulting reaction forces, the sphere rotated.

The second principle is based on the conversion of the potential energy of steam into kinetic energy. It can be illustrated by the example of Giovanni Branca's machine, built in 1629 and shown in figure 2.2. In this machine, a jet of steam set in motion a wheel with paddles, reminiscent of the wheel of a water mill.

The steam turbine uses both of these principles. A jet of steam under high pressure is directed to curved blades mounted on discs. When flowing around the blades, the jet is deflected, and the disk with the blades begins to rotate. Moving between the blades in an expanding channel (after all, the thickness of the blades decreases as it approaches the shank), the steam expands and accelerates. In accordance with the laws of conservation of energy and momentum, a force acts on the turbine wheel, spinning it. As a result, the pressure energy (potential energy) of the steam is converted into the kinetic energy of the turbine rotation.

The first turbines, like Branca's machine, had limited power, because steam boilers were not able to create high pressure. As soon as it became possible to obtain high-pressure steam, the inventors again turned to the turbine. In 1815, engineer Richard Trevithick installed two nozzles on the wheel rim of a steam locomotive and forced steam through them. The device of the sawmill, built in 1837 by the American William Avery, was based on a similar principle. In England alone for 20 years, from 1864 to 1884, more than a hundred inventions were patented, one way or another relating to turbines. But none of these attempts resulted in the creation of a machine suitable for industry.

In part, these failures were due to a misunderstanding of the physics of steam expansion. The fact is that the density of steam is much less than the density of water, and its "elasticity" is much greater than the elasticity of the liquid, so the speed of the steam jet in steam turbines is much greater than the speed of water in water turbines. It was experimentally found that the efficiency The turbine reaches its maximum when the peripheral speed of the blades is approximately half the speed of the steam jet. It is for this reason that the first turbines had very high rotational speeds.

But a high rotational speed often led to the destruction of the rotating parts of the turbine due to the action of centrifugal forces. A decrease in the angular velocity while maintaining the circumferential velocity could be achieved by increasing the diameter of the disk on which the blades were attached. However, it was difficult to implement this idea, since the amount of high-pressure steam produced was not enough for the machine. big size. In this regard, the first experimental turbines had a small diameter and short blades.

Another problem related to the properties of steam was even more difficult. The speed of the steam escaping from the nozzle is proportional to the ratio of the pressures at the inlet and outlet of the nozzle and reaches its maximum value at a pressure ratio of approximately two. A further increase in the pressure drop no longer leads to an increase in the jet velocity. Thus, designers could not take full advantage of high pressure steam when using a constant or tapering bore nozzle.

In 1889, the Swedish engineer Carl Gustav de Laval used a nozzle that expands at the outlet. Such a nozzle made it possible to obtain a much higher steam velocity, and as a result, the speed of rotation of the turbine rotor also increased significantly.

Figure 2.4 shows a Laval steam turbine. In it, steam enters the nozzle, acquires a significant speed in it, and is directed to the working blades located on the rim of the turbine disk. When the steam jet turns in the channels of the working blades, forces arise that spin the disk and the turbine shaft associated with it. Very high steam flow rates are required to produce the required power in a single-stage turbine. By changing the configuration of the expanding nozzle, it was possible to obtain a significant degree of steam expansion and, accordingly, a high speed (1200 ... 1500 m / s) of steam outflow.

To make better use of high steam speeds, Laval developed a disc design that could withstand circumferential speeds of up to 350 m/s, and the speed of some turbines reached 32,000 min-1.

Turbines, in which the entire process of steam expansion and the associated acceleration of the steam flow occurs in nozzles, are called active. Such devices, in particular, include the Branca turbine.

Subsequently, the improvement of active steam turbines followed the path of using sequential expansion of steam in several stages located one after another. In such turbines, developed at the end of the last century by the French scientist Rato and improved by the designer Celli, a number of disks mounted on a common shaft are separated by partitions. In these partitions, profiled holes were arranged - nozzles. At each of the stages constructed in this way, a part of the steam energy is used. The transformation of the kinetic energy of the steam flow occurs without additional expansion of the steam in the channels of the rotor blades. Active multistage turbines are widely used in stationary installations, as well as as marine engines.

Along with turbines in which the steam flow moves approximately parallel to the axis of the turbine shaft and which are called axial turbines, so-called radial turbines have been created in which steam flows in a plane perpendicular to the axis of the turbine. Among this type of turbines, the turbine of the Jungström brothers, proposed in 1912, is of the greatest interest.

On the side surfaces of the disks, the blades of the jet stages are arranged in rings of gradually increasing diameter. Steam is supplied to the turbine through pipes and then through holes in the disks it is directed to the central chamber. Steam flows from it to the periphery through the channels of the blades mounted on the disks. Unlike a conventional turbine, there are no fixed nozzles or guide vanes in the Jungström brothers' design. Both disks rotate in opposite directions, so the power developed by the turbine is transmitted to two shafts. The turbine of the described design turned out to be very compact.

And yet, despite a number of new design solutions used in single-stage active turbines, their efficiency was low. In addition, the need for a reduction gear to reduce the rotational speed of the drive shaft of the electric generator hampered the spread of single-stage turbines. Therefore, Laval turbines, which were widely used at an early stage of turbine construction as units of small power (up to 500 kW), later gave way to turbines of other types.

Parsons created a turbine of a fundamentally new design. It was distinguished by a lower rotational speed, and at the same time, the steam energy was used to the maximum in it. The fact is that in the Parsons turbine, the steam expanded gradually as it passed through 15 stages, each of which consisted of two crowns of blades: one was fixed (with guide vanes fixed on the turbine housing), the other was movable (with rotor blades on the disk). attached to a rotating shaft). The planes of the blades of the fixed and movable rims were mutually perpendicular.

The steam directed to the fixed blades expanded in the interscapular channels, its speed increased, and when it fell on the movable blades, it made them rotate. In the interblade channels of the movable blades, the steam further expanded, the jet velocity increased, and the emerging reactive force pushed the blades.

Thanks to the introduction of movable and fixed blade rims, high rotation speed has become unnecessary. On each of the thirty rims of Parsons' multi-stage turbine, the steam expanded slightly, losing some of its kinetic energy. At each stage (pair of crowns), the pressure dropped by only 10%. The staged expansion of steam, which underpins modern turbine designs, was just one of many original ideas embodied by Parsons.

Another fruitful idea was the organization of steam supply to the middle part of the shaft. Here the steam flow was divided and went in two directions to the left and right ends of the shaft. The steam flow in both directions was the same. One of the benefits of splitting the flow was that the longitudinal (axial) forces due to the pressure of the steam on the turbine blades were balanced. Thus, there was no need for a thrust bearing. The described design is used in many modern steam turbines.

And yet, Parsons' first multi-stage turbine had too high a speed of 18,000 min-1. The centrifugal force acting on the turbine blades was 13,000 times greater than gravity. In order to reduce the risk of breaking rotating parts, Parsons came up with a simple solution. Each disk was made from a solid copper ring, and the slots into which the blades entered were located around the circumference of the disk and were slots oriented at an angle of 45°. Movable disks were mounted on the shaft and fixed on its ledge. The fixed crowns consisted of two half-rings, which were attached from above and below to the turbine housing. The blades of the Parsons turbine were flat. To compensate for the decrease in the steam flow rate as it moves to the last stages, two technical solutions were implemented in the first Parsons machine: the diameter of the disk increased in steps and the length of the blades increased from 5 to 7 mm. The edges of the blades were chamfered to improve the conditions of the jet flow.

Parsons was the youngest son of a family that received land in Ireland. His father, Count Ross, was a talented scientist. He made a great contribution to the technology of casting and polishing large mirrors for telescopes.

The Parsons did not send their children to school. Their teachers were astronomers, whom the count invited for night observations with telescopes; during the daytime, these scholars taught children. In every possible way, children were encouraged to take part in home workshops.

Charles entered Trinity College in Dublin, and then moved to St. John's College, Cambridge University, from which he graduated in 1877.

A turning point in Parsons' fortunes came when he became an apprentice to George Armstrong, a well-known naval gun manufacturer, and began working at his Elswick factory in Newcastlepon Tyne. The reasons that prompted Parsons to make such a decision remained unknown: at that time, children from wealthy families rarely chose a career in engineering. Parsons gained a reputation as Armstrong's most industrious student. During his internship, he received permission to work on the latest innovation - a steam engine with rotating cylinders - and between 1877 and 1882. He patented several of his inventions.

Parsons began his first experiments with turbines while working for Armstrong. From 1881 to 1883, i.e. immediately after the internship, he worked on the creation of a gas-powered torpedo. The peculiarity of the torpedo propulsor was that the burning fuel created a high-pressure gas jet. The jet hit the impeller, causing it to rotate. The impeller, in turn, drove the propeller of the torpedo into rotation.

Parsons stopped work on gas turbines in 1883, although his 1884 patent describes the modern cycle of such a turbine. He later gave an explanation for this. “Experiments conducted many years ago,” he wrote, “and partly aimed at verifying the reality of a gas turbine, convinced me that with the metals that we had at our disposal ... it would be a mistake to use an incandescent jet of gases - whether in pure form, or mixed with water or steam. It was a prescient remark: it was not until ten years after Parsons' death that metals appeared that possessed the necessary qualities.

In April 1884 he filed two provisional patents, and in October and November of that year he gave a full description of the invention. It was an incredibly productive period for Parsons. He decided to create a dynamo, powered by a turbine at high speeds, which are available to few of the modern electric machines. Subsequently, Parsons often repeated that this invention was as important as the creation of the turbine itself. Until today, the main application of the steam turbine has been to drive electrical generators.

In November 1884, when the first prototype of the turbine was created, the Honorable Charles A. Parsons was only 30 years old. Engineering genius and a flair for the needs of the market were not in themselves sufficient conditions for his offspring to successfully enter into life. At a number of stages, Parsons had to invest his own funds so that the work done was not in vain. During a trial in 1898 to extend the validity of some of his patents, it was found that Parsons had spent £1,107.13 10d. of personal money on the turbine.

The 12th century was marked by the appearance of the first steam engine. This was the event when mechanized machines appeared in industry and technology, gradually replacing human labor. The development of industry did not stand still. The whole history of its development is characterized by the search for solutions by inventors different countries one task - the creation of a pore turbine.

It can be argued that the history of the invention of turbines dates back to the 19th century, when the Swedish scientist Carl Patrick Laval invented the milk separator. In search of a solution to the problem of increasing the speed in this device, Karl invented a steam turbine, which was designed in late XIX century. The turbine looked like a wheel with blades, a jet of steam coming out of the pipe pressed on these blades and the wheel spun. The scientist selected tubes for supplying steam of various sizes and shapes. long time, and as a result of lengthy experiments, he concluded that the tube should be cone-shaped. This device is still in use today, and is called the Laval nozzle. Despite the fact that Laval's invention was a fairly simple device at first glance, it became a marvel of engineering. And after a certain period of time, scientists - theorists proved that the invention of steam turbines using the Loval nozzle gives the highest result.

Further, the history of the invention of turbines advances to the beginning of the 20th century, when the French inventor Auguste Rato designed a multi-stage steam turbine, in which the optimal pressure drops for each of the turbine stages were calculated.

After all, the American scientist Glenn Curtis developed a turbine that used a completely new system, it had a small size and a reliable design. These turbines were used in the design of ship propulsion systems, they were installed first on destroyers, then on warships, and finally on passenger ships.

Thus, the history of the invention of turbines reveals several ways to find a convenient and economical heat engine. scientists XIX centuries. Some inventors developed in which the fuel would burn in the cylinder, so such an engine would fit well in vehicles. It was improved by other scientists in order to increase its power and efficiency.

To date, the history of the invention of turbines begins with such great names as Laval, Parsons and Curtis. All these scientists and inventors have made a huge contribution to the development of industry and transport communications throughout the world. All their achievements were of great importance for all mankind. And the most important was the spread of this type of energy as electricity. At present, the inventions of these scientists are widely used throughout the world in the construction of ships and power plants.

By the end of the last century, the industrial revolution had reached a turning point in its development. A century and a half earlier, steam engines had improved significantly - they could run on any type of fuel and set in motion a wide variety of mechanisms. Big influence to improve the design of steam engines had such a technical achievement as the invention of the dynamo, which made it possible to obtain electricity in large quantities. As human demand for energy increased, so did the size of steam engines, until their dimensions were constrained by limitations on mechanical strength. For the further development of industry, a new method of obtaining mechanical energy was required.

This method appeared in 1884, when an Englishman (1854-1931) invented the first turbogenerator suitable for industrial use. Ten years later, Parsons began to study the possibility of applying his invention to vehicles. Several years of hard work paid off: the steamer Turbinia, equipped with a turbine, reached a speed of 35 knots - more than any ship in the Royal Navy. Compared to reciprocating piston steam engines, turbines are more compact and simpler. Therefore, over time, when power and efficiency turbines have increased significantly, they have replaced the engines of previous designs. Currently, steam turbines are used all over the world in thermal power plants as drives for electric current generators. As for the use of steam turbines as engines for passenger ships, their undivided dominance was put to an end in the first half of our century, when diesel engines became widespread. The modern steam turbine inherited many of the features of the first machine invented by Parsons.

Reactive and active principles underlying the operation of a steam turbine. The first of them was used in the “eolipil” device (a), invented by Heron of Alexandria: the sphere in which the steam is located rotates due to the action of the reaction forces that arise when the steam leaves the hollow tubes. In the second case (b), the steam jet directed at the blades is deflected and due to this the wheel rotates. The turbine blades (c) also deflect the steam jet; in addition, passing between the blades, the steam expands and accelerates, and the resulting reaction forces push the blades.

The operation of a steam turbine is based on two principles of creating a circumferential force on the rotor, known since ancient times - reactive and active. Back in 130 BC. Hero of Alexandria invented a device called the aeolipil. It was a hollow sphere filled with steam with two L-shaped nozzles located on opposite sides and directed in different directions. Steam flowed out of the nozzles at high speed, and due to the resulting reaction forces, the sphere began to rotate.

The second principle is based on the conversion of the potential energy of steam into kinetic energy, which does useful work. It can be illustrated by the example of Giovanni Branchi's machine, built in 1629. In this machine, a jet of steam set in motion a wheel with paddles, reminiscent of a water mill wheel.

The steam turbine uses both of these principles. A jet of high-pressure steam is directed onto curved blades (similar to fan blades) mounted on a disc. When flowing around the blades, the jet is deflected, and the disk with the blades begins to rotate. Between the blades, the steam expands and accelerates its movement: as a result, the pressure energy of the steam is converted into kinetic energy.

The first turbines, like Branca's machine, could not develop sufficient power, since steam boilers were not capable of creating high pressure. The first working steam engines of Thomas Savery, Thomas Newcomen and others did not need high pressure steam. The low pressure steam displaced the air under the piston and condensed, creating a vacuum. The piston under the action of atmospheric pressure descended, producing useful work. Experience in building and using steam boilers for these so-called atmospheric engines gradually led engineers to design boilers capable of generating and maintaining pressures far greater than atmospheric pressure.

With the advent of the possibility of obtaining high-pressure steam, the inventors again turned to the turbine. Various design options have been tried. In 1815, engineer Richard Trevithick tried to install two nozzles on the wheel rim of a steam locomotive engine and pass steam from a boiler through them. Trevithick's plan failed. A sawmill built in 1837 by William Avery in Syracuse, New York, was based on a similar principle. In England alone, over 100 years, from 1784 to 1884, 200 inventions were patented, one way or another related to turbines, and more than half of these inventions were registered in the twenty-year period - from 1864 to 1884.

None of these attempts resulted in an industrially usable machine. In part, these failures were due to ignorance of the physical laws that describe the expansion of steam. The density of steam is much less than the density of water, and its "elasticity" is much greater, so the speed of the jet of steam in steam turbines is much greater than the speed of water in water turbines, which the inventors had to deal with. It was found that the efficiency the turbine becomes maximum when the speed of the blades is approximately equal to half the speed of the steam; therefore, the first turbines had very high rotational speeds.

A large number of revolutions was the cause of a number of undesirable effects, among which the danger of destruction of rotating parts under the action of centrifugal forces played an important role. The speed of rotation of the turbine could be reduced by increasing the diameter of the disk on which the blades were attached. However, this was not possible. The steam flow in early devices could not be large, which means that the cross section of the outlet could not be large either. Due to this reason, the first experimental turbines had a small diameter and short blades.

Another problem related to the properties of steam was even more difficult. The speed of the steam passing through the nozzle changes in proportion to the ratio of the inlet pressure to the outlet pressure. The maximum velocity in the converging nozzle is achieved, however, at a pressure ratio of approximately two; a further increase in the pressure drop no longer affects the increase in jet velocity. Thus, the designers could not take full advantage of the possibilities of high pressure steam: there was a limit to the amount of energy stored by high pressure steam that could be converted into kinetic energy and transferred to the blades. In 1889, the Swedish engineer Carl Gustav de Laval used a nozzle that expands at the outlet. Such a nozzle made it possible to obtain much higher steam velocities, and as a result, the rotor speed in the Laval turbine increased significantly.

Parsons created a fundamentally new turbine design. It was distinguished by a lower rotation speed, and at the same time, it made the most of the steam energy. This was achieved due to the fact that in the Parsons turbine, the steam expanded gradually as it passed through 15 stages, each of which was a pair of blade crowns: one was fixed (with guide vanes fixed to the turbine casing), the other was movable (with rotor blades). on a disk mounted on a rotating shaft). The blades of the fixed and movable rims were oriented in opposite directions, i.e. so that if both crowns were movable, then the steam would make them rotate in different directions.

The crowns of the turbine blades were copper rings with blades fixed in slots at an angle of 45°. The movable crowns were fixed on the shaft, the fixed ones consisted of two halves rigidly connected to the body (the upper half of the body was removed).

Alternating movable and fixed rims of the blades (a) set the direction of steam movement. Passing between the fixed blades, the steam expanded, accelerated and was directed to the moving blades. Here, too, the steam expanded, creating a force that pushed the blades. The direction of steam movement is shown on one of the 15 pairs of crowns (b).

The steam directed to the fixed blades expanded in the interblade channels, its speed increased, and it was deflected so that it fell on the movable blades and forced them to rotate. In the interblade channels of the movable blades, the steam also expanded, an accelerated jet was created at the exit, and the resulting reactive force pushed the blades.

With many movable and fixed blade rims, high rotation speed became unnecessary. On each of the 30 rims of the Parsons multi-stage turbine, the steam expanded slightly, losing some of its kinetic energy. At each stage (pair of crowns), the pressure dropped by only 10%, and maximum speed the steam as a result turned out to be equal to 1/5 of the jet velocity in a turbine with one stage. Parsons believed that with such small pressure drops, steam can be considered as a slightly compressible liquid, similar to water. This assumption enabled him to make calculations of steam velocity, efficiency, with a high degree of accuracy. turbines and blade shapes. The idea of ​​stepped expansion of steam, which underpins the design of modern turbines, was just one of many original ideas that Parsons embodied.

Another invention was a new type of bearing designed specifically for a rapidly rotating shaft. Although Parsons managed to reduce the speed of rotation of the turbine, it still remained ten times higher than that of other engines. Therefore, the inventor had to deal with a phenomenon known as "shaft beat". Already at that time it was known that each shaft has its own characteristic critical rotation speed, at which even a small imbalance creates a significant bending force. It turned out that the critical speed of rotation is related to the natural frequency of the transverse vibrations of the shaft (at this frequency, the shaft begins to resonate and collapse). Parsons and de Laval independently found that at speeds greater than critical, the shaft rotates steadily. Despite this, a small imbalance still led to the deviation of the shaft from the equilibrium position. Therefore, in order to avoid damage to the shaft, it should be installed in bearings that would allow its small lateral displacements.

Initially, Parsons tried to use a conventional bearing mounted on springs, but found that this design only increased the vibration. In the end, he came up with a bearing, consisting of a set of rings. Parsons used two sizes of rings: one snug against the inner bearing shell (through which the shaft passed) but did not touch the housing; they alternated with other rings that fit snugly against the case without touching the liner. The entire system of rings in the longitudinal direction was compressed by a spring. This design allowed small lateral displacements of the shaft and at the same time suppressed vibrations due to friction between the two types of washers.

The bearing on the shaft allowed small lateral displacements of the shaft, but damped the vibrations. It consisted of alternating rings: some tightly covered the liner (inside which the shaft passed), without touching the turbine housing, others pressed tightly against the housing without touching the liner. The entire set of rings was compressed by a spring. The screw pump (left) drove oil (yellow) into the bearing.

This design worked successfully, and those who saw the turbine exhibited at the Inventors' Exhibition in London in 1885 noted how smooth it ran compared to other steam engines of the time. The latter shook the foundation so much that the vibration was felt even at a considerable distance from the machine.

The Parsons turbine generator, built in 1884, was the first steam tube to be put into industrial use. Steam under high pressure entered the turbine through a rectangular hole located near the middle of the shaft. Here it was divided and directed to the opposite ends of the shaft, passing through the crowns of the blades. The expanding steam rotated the movable (working) rings, tightly seated on the central shaft. Between the movable rings there were rims of fixed blades fixed on the inner surface of the turbine housing. The fixed blades directed steam to the blades of the moving wheels.
In the interblade space of each wheel, the steam expanded. The principle of multi-stage expansion of steam allowed Parsons to take full advantage of the energy of steam under high pressure and avoid a large number revolutions. The shaft rotated the dynamo, or electric generator (right).

In the Parsons turbine, steam was supplied through a control valve to the middle part of the shaft. Here, the steam flow was divided and went through two channels: one steam went to the left end of the shaft, the other to the right. The volume of steam in both channels was the same. Each jet passed through the crowns of the blades in the turbine.

One of the benefits of splitting the flow was that the longitudinal (axial) forces generated by the pressure of the steam on the turbine blades were exactly balanced. Thus, there was no need for a thrust (axial) bearing. The described design is used in many modern steam turbines.

And yet, Parsons' first multi-stage turbine developed a high speed - 18,000 rpm. At such speeds, the centrifugal force acting on the turbine blades was 13 thousand times greater than the force of gravity. In order to reduce the danger of breaking rotating parts, Parsons developed a very simple design: each disc was made from a solid copper ring; the slots, which included the blades, were located around the circumference of the disk and were slots oriented at an angle of 45°. Movable disks were mounted on the shaft and fixed on its ledge. The fixed crowns consisted of two half-rings, which were attached from above and below to the turbine housing. The increase in the volume of steam during its stepwise expansion required that the length of the blades along the course of the steam increase three times sequentially - from 5 to 7 mm. The edges of the blades have been chamfered to improve jet characteristics.

The problem of reducing the speed of rotation of the shaft gave rise to other inventions. The speeds were so high that it was impossible to solve this problem using the then existing transmission mechanisms (such as gears). It was also impossible to use the simple centrifugal regulator found in earlier designs of steam engines: the regulator balls would simply be torn off by centrifugal force. Parsons developed an entirely new type of regulator. On the turbine shaft, he placed a centrifugal fan connected to a system of tubes containing air. A rotating fan sucked air out of the tubes, creating a vacuum in them. This vacuum was reacted by a leather diaphragm located on the other side of the tube system and connected to a control valve that controlled the steam supply to the turbine. If the speed of rotation of the turbine increased, the rarefaction of air in the tubes increased and the diaphragm arched more; as a result, a valve connected to the diaphragm reduced the steam supply to the turbine and its rotation slowed down.

The regulator worked well, but was not very sensitive. The Parsons turbine drove a dynamo (electric generator). At the time Parsons built his turbine, one incandescent lamp cost as much as a quarter ton of coal. In order to prevent the lamps from burning out during sudden changes in electric current (which often happened if steam engines were used), the dynamo had to provide a constant voltage with an accuracy of 1-2%. For this purpose, Parsons provided his turbine with a special fine adjustment mechanism that responded directly to changes in voltage on the dynamo.

The voltage on the winding of the dynamo is proportional to the intensity magnetic field created at the poles. Parsons made a yoke out of soft iron and fixed it over the dynamo poles by attaching a spring to it. The rocker, overcoming the resistance of the spring, sought to turn in the direction of the magnetic field; the angle of rotation depended directly on the field strength, which in turn was related to the voltage on the windings of the dynamo. Together with the rocker, a copper valve turned. Depending on its position, it to a greater or lesser extent covered the opening of the tube included in the regulator system with a centrifugal fan,

If the strength of the magnetic field grew, the valve began to gradually block the opening of the tube. This reduced the access of air to the regulator system and increased the vacuum created by the centrifugal fan. At the same time, the leather diaphragm was bent and the control valve reduced the steam supply to the turbine. Thus, the speed of rotation of the turbine depended on the voltage on the windings of the dynamo. The Parsons fine adjustment mechanism was one of the first servomotors, feedback devices that control flow. a large number energy, consuming a small part of it.

High pressure steam (dark red) enters through a hole at the midpoint of the shaft and passes through the blade crowns to both ends of the shaft. The exhaust steam (light red) enters two cavities connected by an outlet channel at the bottom of the housing. Even further from the center along the axis of the shaft are two other cavities connected by a channel in the upper part of the housing; they are kept under partial vacuum (blue).

Couplings, tightly pressed against the inner surface of the housing due to the pressure difference between the cavities with exhaust steam and partial vacuum, do not allow exhaust steam to escape through the gaps near the surface of the rotating shaft. Lubrication is supplied by a screw pump (left) which pumps oil (yellow) into the bearing on the shaft and to the other bearings. The oil reaches the central bearings through a channel inside the dynamo shaft (center and right). The regulator uses a centrifugal fan (left) that creates a vacuum (blue) in the piping system. A leather membrane connected to a valve that regulates the supply of steam to the turbine is attracted to them when the vacuum is in the tubes.

The fine adjustment mechanism is located at the top of the dynamo. This mechanism changes the flow of air into the tube system depending on the voltage on the windings of the dynamo. Under the action of the vacuum created in the air tubes, the oil from the bearings flows back into the vertical reservoir (left).

The centrifugal fan, which dominated the Parsons regulator, also played an important role in the lubrication system. The high speed of rotation of the turbine shaft required absolutely reliable lubrication. At the end of the shaft, Parsons reinforced a spiral helix, which was immersed in a reservoir of oil and provided lubricant to the bearings on the shaft. Pipes directed oil to the far end of the shaft where the dynamo was located, and a channel inside the dynamo shaft carried oil to the central bearings and cooled the interior of the dynamo. Under the influence of gravity, the oil returned to the central node. The main oil reservoir was connected by a vertical tube to a system of air tubes located directly at the fan. The vacuum created by the fan forced the oil to flow from the central assembly back into the oil reservoir, so that the oil level was sufficient to operate the screw pump.

Another invention of Parsons, also used in modern turbines, was a method to eliminate the leakage of steam through the gaps between the shaft and the turbine casing. Any attempt to make a coupling tight to the shaft would be unsuccessful, since at a critical speed of rotation during a set of revolutions, a lot of friction would be created as a result of the beats. The coupling, designed by Parsons, tightly fitted the shaft and at the same time allowed for small displacements. Upon reaching the operating speed, the clutch acted as a reliable shutter, keeping the exhaust steam inside the turbine casing.

As soon as the turbine reached operating speeds, the clutch was pressed tightly against the shaft under the influence of the pressure difference between the outlet pipe and the chamber, where a partial vacuum was maintained. The exhaust steam went from two cavities (one at each end of the shaft) through an outlet channel at the bottom of the turbine casing. Two other cavities were located farther from the midpoint of the shaft than each of the output cavities. A channel in the upper part of the body connected these extreme cavities. Inside each of the two internal cavities, Parsons placed a sleeve tightly enclosing the shaft. To maintain a partial vacuum in the extreme cavities, Parsons used a steam jet pump. At a small number of revolutions of the turbine, the couplings freely rotated along with the shaft. Upon reaching the operating speed, a pressure difference arose between the internal cavities (where the exhaust steam from the turbine entered) and the outer cavities (where a partial vacuum was maintained). Under the action of a pressure drop, the couplings were tightly pressed against the turbine housing and separated the cavities from each other.

Under what conditions was Parsons' talent formed, thanks to which he managed to overcome difficulties in the way of creating a turbine? Parsons was the youngest son of a landed family at Birr, in County Offaly, Ireland. His father, the third Earl of Ross, was a talented scientist. He made a great contribution to the technology of casting and polishing large mirrors for telescopes. In 1845, in a workshop on his estate, he built a mirror telescope, which for several decades remained the largest telescope in the world. With this telescope, Parsons Sr. discovered a number of spiral nebulae. From 1849 to 1854 he was President of the Royal Society of London. As a member of Parliament, he bought a house in London in order to attend meetings. For part of the year, the whole family lived here, arranging receptions to which representatives of the scientific community were invited.

The Parsons did not send their children to school. Their teachers were astronomers, whom the count invited for night observations with telescopes; during the daytime, these scholars taught children. In every possible way, children were encouraged to take part in home workshops. The craft, which Charles had been introduced to since childhood, played an extremely important role during the period when he was building his turbine.

Charles entered Trinity College, Dublin, and then transferred to St. John's College, Cambridge University, graduating in 1877. He studied mathematics under Edward E. Root, who at that time was studying conditions for the conservation of uniform motion, in particular the use of various mechanical regulators for these purposes.

Up until this time, Parsons had enjoyed the fruits of his privileged upbringing. A turn in his fortunes came when he became an apprentice to George Armstrong, a well-known naval gun manufacturer, and began working at his Elswick factory in Newcastle upon Tyne. The reasons that prompted Parsons to make such a decision remained unknown: at that time, children from wealthy families rarely chose a career in engineering.

Parsons gained a reputation as Armstrong's most industrious student. During his apprenticeship, he received permission to work on the latest innovation - a steam engine with rotating cylinders - and between 1877 and 1882. He patented several of his inventions. If you study these patents, you can find that he used the idea of ​​pressure lubrication a decade earlier than A. Payne, who is famous for his inventions in this area. Before Parsons, droppers were used to lubricate bearings, so bearings required constant monitoring. The idea of ​​forced lubrication played an exceptional role in the creation of high-speed machines, in particular turbines.

The idea of ​​creating a turbine came to Parsons, apparently, when he was still a student. Lord Rayleigh relates the words of one of Parsons' acquaintances from Cambridge, to whom the future inventor showed a toy paper engine: when Parsons blew on the wheels of the toy, they rotated. Parsons said that the rotational speed of this machine would be "ten times more than any other."

Parsons began his first real experiments with turbines while working for Armstrong. From 1881 to 1883, i.e. immediately after his internship, he collaborated with James Kilson to develop a gas-powered torpedo. Armstrong was largely associated with the production of naval weapons and probably supported efforts to develop a new kind of torpedo propulsor. The peculiarity of this mover was that the burning fuel created a jet of high-pressure gas. The jet hit the impeller, causing it to rotate. The impeller, in turn, rotated the propeller of the torpedo.

Parsons' notebooks do not explicitly indicate the design of the impeller, but some idea of ​​it can be obtained by examining a small boat made by Parsons from sheet copper. The boat was driven by a three-bladed propeller located under the hull. The screw was located inside a large ring with 44 spiral slots. The gas escaping in a jet passed through these slots, and due to the force created by the deflection of the flow, the ring began to rotate. Along with it, the propeller also rotated, pushing the boat forward.

So, Parsons conducted his early experiments with gas turbines, and not with steam turbines. He stopped working on them in 1883, although his 1884 patent describes the modern cycle of a gas turbine. He later gave an explanation for this.

"Experiments carried out many years ago - he wrote, - and partly aimed at verifying the reality of a gas turbine, convinced me that with the metals that we had at our disposal ... it would be a mistake to use an incandescent jet of gases to bring the blades into rotation - whether in pure form or mixed with water or ferry."

It was a prescient remark: it was not until ten years after Parsons' death that metals appeared that were suitable for the manufacture of gas turbines.

Early in 1884 Parsons became a junior partner in Clarke Chapman and Company. After settling in Gateshead, he set about designing a steam turbine. His records of experiments on the creation of a torpedo, relating to August 1883, indicate that at that time he had not yet come to the idea of ​​the need to bring the speed of rotation of the blades to the speed of the gas jet. The problem of creating a nozzle with a large value of the ratio of pressures at the inlet and outlet did not occupy his attention. But already in April 1884 he filed two preliminary patents, and in October and November of the same year he gave a complete description of the invention.

It was an incredibly productive period for Parsons. He had to not only experiment with high-speed shafts and other turbine parts, but also think about possible ways to use the energy of his machine. With a rotation speed of 18,000 rpm, it could not be used for ordinary purposes. Parsons also decided to create a dynamo, powered by a turbine at high speeds, which few modern electric machines can achieve. Subsequently, Parsons often repeated that this invention was as important as the creation of the turbine itself. Until today, the main application of the steam turbine has been to drive electrical generators.

THE FIRST steam turbines were not particularly efficient. Until their power output matched the economy of conventional steam engines, they had to be made attractive to buyers at the expense of other features. Such attractive features are their small size, stability of electrical voltage, reliable operation in the absence of control and low operating costs. All these features were possessed by the first turbine.

In November 1884, when the first prototype of the turbine was created, the Honorable Charles A. Parsons was only 30 years old. Engineering genius and a flair for the needs of the market were not in themselves sufficient conditions for his offspring to successfully enter into life. At a number of stages, Parsons had to invest his own funds so that the work done was not in vain. During a trial in 1898 to extend the validity of some of his patents, it was found that Parsons had spent £1,107.13 10d. of personal money on the turbine.

Turbinia is the first steamship with a turbine engine. It was launched in 1894.
The steamer developed a record speed - up to 35 knots.
Subsequently, turbines began to be used on large ships.