School project on the theme of the steam turbine. Physics presentation on steam and gas turbines

Subject Physics

Class 8 a class

Lesson on the topic “Steam turbine. Gas turbine. heat engine efficiency. Environmental problems use of heat engines.

Basic textbook A.V. Peryshkin Physics 8; M.: Bustard

The purpose of the lesson:

Educational

to provide during the lesson the study of the device, the principle of operation of the steam and jet turbine;

to form in students the concept of the efficiency of a heat engine and consider ways to improve it;

reveal the role and significance of TD in modern civilization

to promote the ability to compare the efficiency of a real and ideal heat engine;

show the positive and negative role of heat engines in human life.

Educational

continue developing the ability to analyze, highlight the main thing in the material being studied, compare, systematize and draw conclusions;

development of the horizons of students and their acquisition of new natural science knowledge

Educational

continue the formation of a scientific worldview and show that knowledge is based on facts obtained from experience, show the infinity of the process of knowledge;

Lesson type: Combined

Forms of work of students: individual and collective, observations.

Necessary Technical equipment: computer, projector

Structure and course of the lesson

1. Organizational stage.

* checking the presence of students in the class;

* reminder TB work in the office;

* friendly attitude of the teacher and students;

* organizing the attention of all students;

* message topics and objectives of the lesson.

2. The stage of updating the basic knowledge:

Frontal discussion on:

1) What engine is called an internal combustion engine?

2) What are the main parts of the simplest internal combustion engine?

3) What physical phenomena occur during the combustion of a combustible mixture in an internal combustion engine?

3. The stage of learning new material.

1. Setting the goal of the lesson.

2. Learning concepts " steam turbine» «gas turbine», «heat engine efficiency», impact of heat engines on the environment

STEAM TURBINE

“In the previous lessons, we got acquainted with the internal combustion engine. Today we will get acquainted with another type of engine in which steam or gas heated to high temperature rotates the engine shaft without the help of a piston, connecting rod and crankshaft "
(see slide 4 "Steam turbine model")

Demo comments:

steam creating pressure on the turbine blades causes it to rotate along with the shaft on which it is located and lift the weight attached to the thread

(see slide 5 "Steam turbine")

Practical use This process has been widely used in the energy industry.

(see slide 6 "The operation of a thermal power plant") .

Slide comments.

The principle of operation of CHP:

Turbine - generator - electric current

other steam turbine applications:

GAS TURBINE

An example of an engine in which gas heated to a high temperature rotates the engine shaft(see slide 7 "Jet engine") :

Comments:

When the turbine is running, the rotor compressor rotates and sucks air through inlet nozzle . The air, passing through a series of compressor blades, is compressed, its pressure and temperature increase. Compressed air enters combustion chambers . At the same time through the nozzle, it is injected into it under high pressure liquid fuel(kerosene, fuel oil). When burning fuel, the air heats up to 1500-2200 0 C. The air expands and its speed increases. Air and combustion products moving at high speed are sent to gas turbine . Passing from stage to stage, they give their kinetic energy to the blades of the turbine rotor, while their temperature decreases to 550 0 C. Part of the energy received by the turbine is spent on the rotation of the compressor, and the rest is used, for example, to rotate the aircraft propeller or rotor electric generator. Exhaust air together with combustion products at a pressure close to atmospheric and at a speed of more than 500 m/s are thrown out through outlet nozzle to atmosphere.

Application in aviation, energy, etc.

HEAT ENGINE EFFICIENCY:

We look at slide 8 "Efficiency of heat engines"

definition of efficiency We look at slide 9 "Values ​​of the efficiency of various heat engines"-

we pronounce the types of engines and the efficiency of engines

ENVIRONMENTAL PROBLEMS OF THE USE OF THERMAL MACHINES

ways to reduce the harmful impact on the environment:

watch an interactive lecture "Environmental problems of using heat engines"

We look at slide 10 "It's interesting ..."

Interesting fact!

The combustion of fuel is accompanied by the release of carbon dioxide into the atmosphere. The Earth's atmosphere currently contains about 2600 billion tons of carbon dioxide (about 0.0033%). Before the period of rapid development of energy and transport, the amount of carbon dioxide absorbed by plants during photosynthesis and dissolved in the ocean was equal to the amount of gas released during respiration and decay. In recent decades, this balance has been increasingly disturbed. At present, about 20 billion tons of carbon dioxide enter the Earth's atmosphere annually due to the combustion of coal, oil and gas.

We look at slide 11 "Environmental problems"

A steam turbine (fr. turbine from lat. turbo whirlwind, rotation) is a continuous heat engine, in the blade apparatus of which the potential energy of compressed and heated water vapor is converted into kinetic energy, which in turn performs mechanical work on the shaft.

The turbine consists of three cylinders (high pressure cylinder, high pressure cylinder and low pressure cylinder), the lower halves of the bodies of which are designated 39, 24 and 18, respectively. Each of the cylinders consists of a stator, the main element of which is a fixed body, and a rotating rotor. Separate rotors of the cylinders (high pressure cylinder rotor 47, TsSD 5 rotor and LPC rotor 11) are rigidly connected by couplings 31 and 21. The half coupling of the electric generator rotor is attached to the coupling half 12, and the exciter rotor is connected to it. A chain of assembled separate rotors of cylinders, a generator and an exciter is called a shaft line. Its length with a large number of cylinders (and the largest number in modern turbines is 5) can reach 80 m.

Principle of operation Steam turbines work as follows: steam generated in a steam boiler, under high pressure, enters the turbine blades. The turbine rotates and generates mechanical energy used by the generator. The generator produces electricity. The electric power of steam turbines depends on the pressure difference between the steam at the inlet and outlet of the plant. The power of steam turbines of a single installation reaches 1000 MW. Depending on the nature thermal process steam turbines are divided into three groups: condensing, heating and turbine special purpose. According to the type of turbine stages, they are classified as active and reactive.

Steam turbines - advantages Steam turbines can be operated on various types fuels: gaseous, liquid, solid operation of steam turbines is possible on various types of fuel: gaseous, liquid, solid high unit power high unit power free choice of coolant free choice of coolant wide power range wide power range

Steam turbines - disadvantages high inertia of steam plants (long start and stop times) high inertia of steam plants (long start and stop times) high cost of steam turbines high cost of steam turbines low volume of electricity produced, in relation to the volume of thermal energy low volume of electricity produced, in the ratio with the volume of thermal energy Expensive repair of steam turbines Expensive repair of steam turbines Reduced environmental performance, in the case of heavy fuel oil and solid fuel reduction of environmental performance, in the case of the use of heavy fuel oils and solid fuels

Applications: The Parsons jet steam turbine was used for some time mainly on warships, but gradually gave way to more compact combined active-reactive steam turbines, in which the high-pressure reactive part was replaced by a single or double-crowned active disk. As a result, losses due to steam leakage through the gaps in the blade apparatus have decreased, the turbine has become simpler and more economical. Depending on the nature of the thermal process, steam turbines are usually divided into 3 main groups: condensing, cogeneration and special purposes.

Main advantages of PTM: Wide power range; Increased (by 1.2-1.3 times) internal efficiency (~75%); Significantly reduced installation length (up to 3 times); Low capital costs for installation and commissioning; Lack of an oil supply system, which ensures fire safety and allows operation in the boiler room; The absence of a gearbox between the turbine and the driven mechanism, which increases the reliability of operation and reduces the noise level; Smooth regulation of the shaft rotation speed from idling to the load of the turbine plant; Low noise level (up to 70 dBA); Low specific gravity (up to 6 kg / kW of installed power) High service life. The operating time of the turbine before decommissioning is at least 40 years. With seasonal use of the turbine, the payback period does not exceed 3 years.

A turboelectric generator based on a steam turbine of the PTM type compares favorably with other energy sources due to increased internal efficiency, long service life, small dimensions, smooth control over a wide range of loads, lack of an oil supply system and ease of installation.

slide 2

A steam turbine (fr. turbine from lat. turbo whirlwind, rotation) is a continuous heat engine, in the blade apparatus of which the potential energy of compressed and heated water vapor is converted into kinetic energy, which in turn performs mechanical work on the shaft.

slide 3

The turbine consists of three cylinders (high pressure cylinder, high pressure cylinder and low pressure cylinder), the lower halves of the cases of which are designated 39, 24 and 18, respectively. Each of the cylinders consists of a stator, the main element of which is a fixed housing, and a rotating rotor. Separate rotors of the cylinders (high pressure cylinder rotor 47, TsSD rotor 5 and LPC rotor 11) are rigidly connected by couplings 31 and 21. The half coupling of the electric generator rotor is attached to the coupling half 12, and the exciter rotor is connected to it. A chain of assembled separate rotors of cylinders, a generator and an exciter is called a shaft line. Its length with a large number of cylinders (and the largest number in modern turbines is 5) can reach 80 m.

slide 4

Principle of operation

Steam turbines work as follows: steam generated in a steam boiler, under high pressure, enters the turbine blades. The turbine rotates and generates mechanical energy used by the generator. The generator produces electricity. The electric power of steam turbines depends on the pressure difference between the steam at the inlet and outlet of the plant. The power of steam turbines of a single installation reaches 1000 MW. Depending on the nature of the thermal process, steam turbines are divided into three groups: condensing, heating and special-purpose turbines. According to the type of turbine stages, they are classified as active and reactive.

slide 5

slide 6

Steam turbines - advantages

operation of steam turbines is possible on various types of fuel: gaseous, liquid, solid high unit power free choice of coolant wide power range impressive service life of steam turbines

Slide 7

Steam turbines - disadvantages

high inertia of steam plants (long start-up and shutdown times) high cost of steam turbines low volume of electricity produced in relation to the volume of thermal energy expensive repair of steam turbines reduction of environmental performance in the case of heavy fuel oils and solid fuels

Slide 8

Application:

The Parsons jet steam turbine was used for some time mainly on warships, but gradually gave way to more compact combined active-reactive steam turbines, in which the high-pressure reactive part was replaced by a single or double-crowned active disk. As a result, losses due to steam leakage through the gaps in the blade apparatus have decreased, the turbine has become simpler and more economical. Depending on the nature of the thermal process, steam turbines are usually divided into 3 main groups: condensing, cogeneration and special purpose.

Slide 9

The main advantages of PTM:

Wide power range; Increased (by 1.2-1.3 times) internal efficiency (~75%); Significantly reduced installation length (up to 3 times); Low capital costs for installation and commissioning; Lack of an oil supply system, which ensures fire safety and allows operation in the boiler room; The absence of a gearbox between the turbine and the driven mechanism, which increases the reliability of operation and reduces the noise level; Smooth regulation of the shaft rotation speed from idling to the load of the turbine plant; Low noise level (up to 70 dBA); Low specific gravity (up to 6 kg/kW of installed power) High service life. The operating time of the turbine before decommissioning is at least 40 years. With seasonal use of the turbine, the payback period does not exceed 3 years.

Steam turbine (fr. turbine from lat. turbo vortex, rotation) a continuous heat engine, in the blade apparatus of which the potential energy of compressed and heated water vapor is converted into kinetic energy, which in turn performs mechanical work on the shaft. fr. lat. engine potential energy water parakinetic mechanical work

STEAM TURBINE A turbine that converts the thermal energy of water vapor into mechanical work. The flow of water vapor enters through the guide vanes on the curvilinear blades fixed around the circumference of the rotor, and, acting on them, causes the rotor to rotate. Unlike a piston steam engine, a steam turbine uses not potential, but kinetic energy of a steam turbine.

Attempts to create steam turbines have been made for a very long time. A description of a primitive steam turbine made by Heron of Alexandria (1st century BC) is known. However, only at the end of the 19th century, when thermodynamics, mechanical engineering and metallurgy reached a sufficient level, Laval (Sweden) and Parsons (Great Britain) independently created industrially suitable steam turbines.

Laval applied the expansion of steam in fixed conical nozzles in one step from the initial to the final pressure and directed the resulting jet (with a supersonic exhaust velocity) to one row of working blades mounted on a disk. Steam turbines operating on this principle are called active turbines.

Parsons created a multi-stage jet steam turbine in which steam expansion was carried out in a large number of sequentially arranged stages not only in the channels of the fixed (guide) blades, but also between the moving (working) blades. The steam turbine turned out to be a very convenient engine for driving rotary mechanisms (electric current generators, pumps, blowers) and ship propellers; it was faster, more compact, lighter, more economical and more balanced than a reciprocating steam engine.

Silaev Platon,
Goncharova Valeria
8"M" School №188

What's happened?

Turbine is a bladed machine in which
there is a transformation of the kinetic
energy and / or internal energy of the worker
bodies (steam, gas, water) into mechanical work
on the shaft.

Steam turbine.

Steam turbine represents
a drum or series
spinning disks,
fixed on a single axis, their
called the turbine rotor, and
a series of alternating with them
fixed disks,
fixed on the base
called a stator.

History of the invention of turbines

At the heart of the steam turbine
there are two principles of creation
forces on the rotor, known from
ancient times, reactive and
active. In Branque's car
built in 1629, jet
couple set in motion
wheel-like wheel
water mill.

Parsons steam turbine

Parsons connected the steam turbine
with electric generator
energy. With a turbine
it became possible to develop
electricity, and it boosted
public interest in thermal
turbines. As a result of 15 years of research, he created
the most perfect in terms of
sometimes a jet turbine.

Steam turbine applications

Steam turbines

The first forerunner of modern
steam turbines can be considered a toy
engine, which was invented in the 2nd century. before. AD
Alexandrian scholar Heron. First
forerunner of modern steam
turbines can be considered a toy engine,
which was invented in the 2nd century. before. AD
Alexandrian scholar Heron.

First turbine project

In 1629, the Italian Branca created a design for a wheel with blades. It should
was to rotate if the jet of steam hits the wheel blades with force.
It was the first steam turbine project, which subsequently received
the name of the active turbine. In 1629, the Italian Branca created a project
paddle wheels. It had to rotate if the jet of steam with force
hitting the wheel blades. It was the first steam turbine project
which later became known as the active turbine. Steam
the flow in these early steam turbines was not concentrated, and
most of its energy was dissipated in all directions, which
resulted in significant energy losses. Steam flow in these early
steam turbines was not concentrated, and most of it
energy is dissipated in all directions, resulting in
significant energy loss.

Attempts to create a turbine

Attempts to create mechanisms similar to turbines have been made for a very long time.
A description of a primitive steam turbine made by Heron is known.
Alexandria (1st century AD). According to I. V. Linde, the 19th century gave birth to
"a lot of projects" that stopped before "material
difficulties in their implementation. Only at the end of the 19th century, when
development of thermodynamics (increase turbine efficiency to comparable with
reciprocating machine), mechanical engineering and metallurgy (increase
strength of materials and manufacturing precision required for
creation of high-speed wheels), Gustaf Laval (Sweden) and Charles
Parsons (Great Britain) independently created suitable
steam turbines for industry.

First steam turbine

The first steam turbine was created by the Swedish inventor Gustaf Laval. By
one of the versions, Laval created it in order to lead to
actionmilk separator of our own design. For this it was necessary
speed drive. The engines of that time did not provide sufficient
rotation frequency. The only way out was to design
high speed turbine. As a working fluid, Laval chose widely
steam used at that time. The inventor began to work on his
design and eventually assembled a workable device. In 1889
year, Laval supplemented the turbine nozzles with conical expanders, so
the famous Laval nozzle appeared, which became the progenitor of future
rocket nozzles. The Laval turbine was a breakthrough in engineering. Enough
imagine the loads that the impeller experienced in it in order to
to understand how difficult it was for the inventor to achieve stable operation of the turbine.
At huge speeds of the turbine wheel, even a slight shift in
center of gravity caused strong vibration and overload of the bearings.
To avoid this, Laval used a thin axis, which, when rotated
could bend.

Steam turbines are installed on powerful
power stations and large
ships.
For a steam engine to work,
a number of auxiliary machines and devices.
All this together is called
steam power station.

Rotor with blades
- mobile
part of the turbine.
Stator with nozzles
- motionless
part.

Efficiency of heat engines:

Steam
machine 8-12%
ICE 20-40%
Steam
turbine
20-40%
Diesel
30-36%

shortcomings of work
steam turbine
Benefits
steam turbine operation
rotation speed is not
may change in
wide range
long start time and
stops
high cost of steam
turbines
low volume
produced
electricity, in
relation to
the volume of thermal en.
rotation takes place in
one direction;
missing
jolts like at work
piston
steam operation
turbines is possible on
various types
fuel: gaseous,
liquid, solid
high single
power

gas turbine
A gas turbine is a continuous heat engine
action that converts gas energy into mechanical
work on the shaft of a gas turbine. Unlike piston
engine, in a gas turbine engine processes
occur in a moving gas stream. Gas quality
turbine is characterized by efficiency efficiency, that is
the ratio of the work removed from the shaft to the available
gas energy before the turbine
History
creation
1500 - Leonardo da Vinci drew a diagram
grill that uses
gas turbine principle
1903 - Norwegian Aegidius Jelling created the first working
gas
turbine that used
rotary compressor and turbine and
produced useful work.

A gas turbine consists of turbine disks and a compressor,
mounted on one shaft. The turbine works like this: air
is injected by the compressor into the combustion chamber of the turbine, where then
liquid fuel is injected. The combustible mixture burns at very
high temperature, gases expand, rush to
exhaust port, along the way they fall on the turbine blades and
bring them into rotation.

Application
At present, gas turbines are used as the main
marine transport engines.
IN individual cases small gas turbines are used in
as a drive for pumps, emergency power generators, auxiliary
boost compressors, etc.
Of particular interest are gas turbines as the main engines for
hydrofoils and hovercraft.
Gas turbines are also used in locomotives and tanks.

Advantages and disadvantages of gas turbine
engines
Advantages gas turbine engines
The possibility of obtaining more steam during operation (in
different from piston engine)
In combination with a steam boiler and a steam turbine, higher efficiency
compared to a piston engine. Hence their use in
power plants.
Moving only in one direction, with much less
vibration, unlike a piston engine.
Fewer moving parts than a piston engine.
Significantly lower emissions of harmful substances compared to
piston engines
Low cost and consumption of lubricating oil.

Disadvantages of gas turbine engines
The cost is much higher than that of similarly sized piston
engines, since the materials used in the turbine must have
high heat resistance and heat resistance, as well as high specific
strength. Machine operations are also more complex;
In any mode of operation, they have a lower efficiency than piston
engines. Requires an additional steam turbine to boost
efficiency.
Low mechanical and electrical efficiency (gas consumption more than
1.5 times more per 1 kWh of electricity compared to piston
engine)
A sharp decrease in efficiency at low loads (unlike piston
engine)
The need to use high pressure gas, which
necessitates the use of booster compressors with
additional energy consumption and a drop in overall efficiency
systems.