2. BHEL is an integrated power plant equipment manufacturer and one of the
largest engineering and manufacturing companies of its kind in India. The
company is engaged in the design, engineering, manufacture, construction,
testing, commissioning and servicing of a wide range of products and
services for the core sectors of the economy, viz. Power, Transmission,
Industry, Transportation, Renewable Energy, Oil & Gas and Defence with
over 180 products offerings to meet the needs of these sectors.
Supplies steam turbines, generators, boilers and its auxiliaries up to
1000 MW.
Supplies hydro turbines and generators of up to 250MW.
Has proven expertise in plant performance improvement through
renovation, modernization and up rating of a variety of power plant
equipment
3. In the era of Mechanical Engineering, Turbine, A
Prime Mover (Which uses the Raw Energy of a substance and
converts it to Mechanical Energy) is a well-known Machine most
useful in the field of Power Generation. This Mechanical energy is
used in running an Electric Generator which is directly coupled to
the shaft of turbine. From this Electric Generator, we get electric
Power which can be transmitted over long distances by means of
transmission lines and transmission towers. In my Industrial
Training in B.H.E.L., HYDERABAD I go through all sections in
Turbine Manufacturing.
First management team told me about the history of
industry, Area, Capacity, Machines installed & Facilities in the
Industry. After that they told about the gas Turbine its types, parts
like Blades, Casing, Rotor etc. Then they told full explanation of
constructional features and procedure along with equipment used.
They told about the safety precautions, Step by Step arrangement of
machines in the block with a well-defined proper format. They also
told the material of blade for a particular desire, types of Blades,
Operations performed on Blades.
4. Gas turbines are common power generators which are used mainly in power
generation systems and propulsion systems. Most of the gas turbines are
internal combustion machines while the rest are fired externally. The sizes
of gas turbines can vary from 500kW to 250MW according to their
applications.
A typical gas turbine mainly consists of three components namely
compressor
combustion chamber
turbine
5.
6.
7. The Brayton or the Joule cycle is commonly used to analyse the gas
turbine systems and the figure shows a Temperature-Entropy (TS)
diagram representation of an ideal Brayton cycle. In figure 2, from
point 1 to point 2 the air is isentropically compressed and the heat is
supplied at constant pressure from point 2 to point 3. Finally, the air is
isentropically expanded from point 3 to point 4.
8. An aircraft turbine engine is the most widely used propulsion
system in the aviation industry. Turbine engines come in several
types, each with its own requirements for maintenance and
aircraft engine overhaul. That’s why it is important to choose the
right company when performing repairs and maintenance on
your aircraft turbine engine.
Turbojet-
A turbojet is the simplest of all aircraft turbine engines,
consisting of four sections: compressor, combustion chamber,
turbine section and exhaust. In this type of engine, air is passed
at a high rate of speed into the combustion chamber where the
fuel inlet and igniter is located. The turbine, driven by
expanding air, causes thrust from accelerated exhaust
gases. Covington Aircraft has extensive experience in aircraft
engine overhaul, as well as routine maintenance for these types
of engines.
9. Turbo fan-
Merging the best features of the turbojet and turboprop, the
turbofan is an aircraft turbine engine that diverts a secondary flow of air
around the combustion chamber, which creates additional thrust. This is
the most modern version of an aircraft turbine engine and the one often
found on high-speed transport and fighter planes. Because many
corporations choose turbofan engines, Covington Aircraft focuses on
plane maintenance to keep corporate planes in the air, avoiding
grounded aircraft due to maintenance issues.
Turboprop-
Turboprop engines drive propellers through a
reduction gear, which provides optimum propeller
performance at slower rpm speeds. That translates to greater
fuel efficiency and performance at slower airspeeds, which is
why turboprops are popular aircraft turbine engines for small,
commuter aircraft, cargo planes and agricultural use. The
propellers are less efficient as the aircraft speed increases,
making them better for planes that do not have travel at
higher speeds.
10. The stationary nozzle guide vanes are positioned in a ring with convergent
spaces between each vane.
As the gas passes through the vanes it is accelerated and directed at the correct
angle onto the moving turbine rotor blades.
There are three types of turbine rotor blade.
The three types are:
1.impulse blades
2. reaction blades
3.impulse/reaction blades
11. With this type of rotor blade the gas pressure drop occurs in the stationary
nozzle guide vanes.
The converging space between the guide vanes causes the gas to
accelerate so gaining in kinetic energy and losing pressure energy and
temperature.
12. With this type of rotor blade the stationary nozzle guide vanes would simply
redirect the gas onto the blades by giving it a whirling motion.
There would be no acceleration or loss of pressure in the nozzle guide
vanes.
The turbine rotor blades are aerofoil shaped and their inter-blade spaces are
convergent.
13. Aircraft main engines use a combination of impulse and reaction sections in
one rotor blade.
The mix is about half impulse and half reaction.
At half span the section is impulse at the leading edge changing to
reaction towards the trailing edge, (about 50% impulse and 50%
reaction).
14. ISO ambient conditions for the industrial gas turbine are described as follows:
Ambient temperature - 150C/590F
Relative humidity- 60 %
Ambient pressure - 1.013 bar/14.7 psi
Ambient temperature
Increases in the ambient temperature can highly affect the gas turbine
performance. When the inlet air is hot the net power of the gas turbine reduces. For
every 1 0C increment in the ambient temperature the amount of the reduction in
power output is nearly 0.9%. For an increment of the ambient temperature by
one Kelvin above the ISO condition, the reduction of the gas turbine thermal
efficiency is nearly 0.1%.
15. Ambient Pressure
Ambient pressure is a site dependent parameter and it changes with the
elevation. With the increases of the elevation, the density of the air
reduces, thus ambient pressure reduces. As results of that mass flow rate,
fuel rate and the power output of the gas turbine reduce nearly by 3.5%
for each 1000 feet (305m) of elevation above the sea level .
16. Humidity
The humid air has less density than the dry air. As a result of
low-density air, the amount of dry air mass entering into the gas turbine
reduces. Thus, the performance of the gas turbine reduces.
17. Pressure ratio
The amount of compressibility of the compressor can be
considered as the pressure ratio. the efficiency of the open ideal gas turbine
cycle can be derived as:
𝜼 = 𝑵𝒆𝒕𝒘𝒐𝒓𝒌𝒐𝒖𝒕𝒑𝒖𝒕/𝑯𝒆𝒂𝒕𝒔𝒖𝒑𝒑𝒍𝒊𝒆𝒅
= (𝑪𝒑 (𝑻𝟑– 𝑻𝟒) − 𝑪𝒑 (𝑻𝟐 – 𝑻𝟏) )/𝑪𝒑 (𝑻𝟑 – 𝑻𝟐)
From the isentropic temperature and pressure relation :
𝑻𝟐/𝑻𝟏= (𝑷𝟐/𝑷𝟏)(𝜸−𝟏)/𝜸
The efficiency can be shown in term of pressure ratio
𝜼 = 𝟏− (𝟏/𝒓)(𝜸−𝟏)/𝜸)
18. According to the above relation the efficiency of the gas turbine depends only
on the pressure ratio and gamma (𝛾). The efficiency of the gas turbine
increases with the pressure ratio.
19. Turbine inlet temperature-
Turbine inlet temperature (TIT) can be defined as the temperature of the air
gas mixture at the inlet of the gas turbine and it is one of the most critical
parameters which influences the gas turbine performance.
Both the power output and the thermal efficiency can be improved by
increasing the TIT.
20. Isentropic efficiency-
An isentropic process is a constant entropy process and it can be proved that
any adiabatic and reversible process is an isentropic process. An adiabatic
process is one in which no heat is transferred to or from the fluid during the
process while in the reversible process, both the fluid and its surroundings
can always be restored to their original state), but in reality it is hard to find
any reversible process due to losses in the fluid flow path.
Figure represents T-S diagram for the compression and the expansion of
the gas turbine. The process 1 to 2S in figure 10 represents isentropic
compression while process 1 to 2 represents an actual compression.
For the expansion case in figure10 the process 3 to 4S indicates the
isentropic expansion while the process 3 to 4 represents the actual
expansion.
21.
22. This report deals with the manufacturing of gas turbine
mainly rotors in bhel hyderabad and also discuss about the
working principle of power plant and theoretical background
of gas turbines and it discusses about the various
components of gas turbines
