turbines 1 fudamental
TRANSCRIPT
-
7/28/2019 Turbines 1 Fudamental
1/64
1
-
7/28/2019 Turbines 1 Fudamental
2/64
Turbo Mach ine
is defined as a
device that extracts energy from a
continuously
flowing fluid by the dynamic action ofone or more rotating elements .
The prefix turbo is a Latin word
meaning spin orwhirl implying that turbo
machines rotate in some way.
2
-
7/28/2019 Turbines 1 Fudamental
3/64
TypesofTurbines
1. Steam Turbines
2. Gas Turbines (Combustion Turbines)
3. Water (Hydraulic) Turbines
3
-
7/28/2019 Turbines 1 Fudamental
4/64
Steam Turbines
A steam turbine is mainly used as an ideal prime mover in
which heat energy is transformed into mechanical energy in
the form of rotary motion.
A steam turbineis used in
1. Electric power generation in thermal power plants.
2. Steam power plants.
3. To propel the ships, submarines.
In steam turbines, the heat energy of the steam is first
converted into kinetic (velocity) energy which in turn is
transformed into mechanical energy of rotation and then
drives the generator for the power generation.
4
-
7/28/2019 Turbines 1 Fudamental
5/64
Based on action of steam or type of
expansion:1. Impulse or velocity orDe Laval turbine
2. Reaction or pressure orParsons turbine
3. Combination turbineBased on number of stages:
1. Single stage turbine 2. Multi-stage turbine
Based on type of steam flow:1. Axial flow turbine 2. Radial flow turbine
5
-
7/28/2019 Turbines 1 Fudamental
6/64
6
-
7/28/2019 Turbines 1 Fudamental
7/647
-
7/28/2019 Turbines 1 Fudamental
8/64
. The steam is made to
fall in its pressure by
expanding in a nozzle.Due to this fall in
pressure, a certain
amount of heat energy is
converted into kinetic
energy, which sets the
steam to flow with a
greater velocity.
The rapidly moving particles of the steam enter therotating part of the turbine, where it undergoes a
change in the direction of motion, which gives rise
to a change of momentum and therefore a force.
This constitutes the driving force of the turbine. 8
-
7/28/2019 Turbines 1 Fudamental
9/64
9
-
7/28/2019 Turbines 1 Fudamental
10/64
Impulse Turbines (De Laval
Turbine)
In this type of turbine, steam is
ini t ially expanded in a nozzlefrom highpressure to low pressure. High velocity
jet of steam coming out of the nozzle is
made to glide over a curved vane, calledBlade.
10
-
7/28/2019 Turbines 1 Fudamental
11/64
The jet of steam gliding over the blade gets
deflected very closely to surface. This
causes the particles of steam to suffer achange in the direct ion o f mo t ion, which gives
rise to a change of momentumand therefore a
force, which will be centr i fugalin nature.
Resultantof all these centrifugal forces
acting on the entire curved surface of the
blade causes it to move.
11
-
7/28/2019 Turbines 1 Fudamental
12/64
-
7/28/2019 Turbines 1 Fudamental
13/64
Principle of working -
In this type of turbine, thehigh pressure steam does
not initially expand in the
nozzle as in the case of
impulse turbine, but
instead directly passes
onto the moving blades.
13
-
7/28/2019 Turbines 1 Fudamental
14/64
Blade shapes of reaction turbines aredesigned in such a way that the steamflowing between the blades will be
subjected to thenozzle effect
. Hence,the pressure of the steam dropscontinuously as it flows over theblades causing, simultaneous increasein the velocity of the steam.
14
-
7/28/2019 Turbines 1 Fudamental
15/64
Reaction force:
is due to the change inmomentum relative velocity
of the steam while passing
over the blade passage.
Centr i fugal forc e:is the force acting on the
blade due to change in
radius of steam entering
and leaving the turbine.
Resu ltant forc e:
is the resultant of Reaction
force and Centrifugal force.
15
-
7/28/2019 Turbines 1 Fudamental
16/64
16
Fixed BladeMoving Blade
-
7/28/2019 Turbines 1 Fudamental
17/64
Impulse Turbine Reaction Turbine
The steam expands
(pressure drops) completely
in nozzles or in the fixed
blades
The steam expands both in
the fixed and moving blades
continuously as it flows over
them
The blades havesymmetrical profile of
uniform section
The blades have converging(aerofoil) profile
The steam pressure while
passing over the bladesremains constant
The steam pressure while
passing over the bladesgradually drops
Because of large initial
pressure drop, the steam
and turbine speeds are very
Because of gradual pressure
drop, the steam and turbine
speeds are low 17
Difference between Impulse & Reaction Turbines
-
7/28/2019 Turbines 1 Fudamental
18/64
Impulse Turbine Reaction Turbine
Power is obtained only
due to the impulsive force
of the incoming steam
Power is obtained due to
impulsive force of
incoming steam as well as
reaction of exit steam
Suitable for small capacityof power generation &
occupies less space per
unit power
Suitable for medium &high capacity power
generation and occupies
more space per unit power
Efficiency is lesser Efficiency is higher
Compounding is
necessary to reduce
speed
Compounding is not
necessary
18
-
7/28/2019 Turbines 1 Fudamental
19/64
Compounding of Impulse TurbinesAs the complete expansion of steam takes in one stage
(i.e., the entire pressure drop from high pressure to lowpressure takes place in only one set of nozzles), the turbinerotor rotates at very high speed of about 30,000 rpm(K.E. is fully absorbed).
High speed poses number of technical difficulties likedestruction of machine by the large centrifugal forcesdeveloped, increase in vibrations, quick overheating of
blades, impossibility of direct coupling to othermachines, etc.
To overcome the above difficulties, the expansion ofsteam is performed in several stages.
19
-
7/28/2019 Turbines 1 Fudamental
20/64
Utilization of the high pressure energy of
the steam by expanding it in successivestages is calledCompound ing .
Methods ofCompound ing:
Veloc i ty compound ing(Curt is Impulse Turbine)
Pressure compounding
Pressu re-veloc i ty compound ing
20
-
7/28/2019 Turbines 1 Fudamental
21/64
Velocity compounding
Comprise of nozzles and two or more
rows of moving blades arranged in
series. In between two rows ofmoving blades, one set of guide (fixed)
blades are suitably arranged.
Guide (fixed) blades are fixed tocasing and are stationary.
21
-
7/28/2019 Turbines 1 Fudamental
22/64
22
Velocity Compounding (Curtis Impulse Turbine)
N Nozzle
M Moving Blade
F Fixed Blade
-
7/28/2019 Turbines 1 Fudamental
23/64
Pressure compounding
Consists oftwo stage of nozzles
followed by two rows of moving blades.
23
-
7/28/2019 Turbines 1 Fudamental
24/64
24
Pressure Compounding
-
7/28/2019 Turbines 1 Fudamental
25/64
25
Pressure-Velocity Compounding
(Combined Impulse Turbine)
Total pressure drop is divided into two stages & the total
velocity obtained in each stage is also compounded
A Axial clearance, N Nozzle, M Moving Blade, F Fixed Blade
Pi and Pe Pressure at inlet & exit, Vi and Ve - Velocity at inlet & exit
-
7/28/2019 Turbines 1 Fudamental
26/64
26
-
7/28/2019 Turbines 1 Fudamental
27/64
27
-
7/28/2019 Turbines 1 Fudamental
28/64
A Gas turbineuses the hot gases ofcombustion directly to produce the
mechanical power.
Fuels used - Kerosene, coal, coal gas,
bunker oil, gasoline, producer gas, etc.,
Classification:1. Open cycle gas turbine
2. Closed cycle gas turbine
28
-
7/28/2019 Turbines 1 Fudamental
29/64
ApplicationsGas turbines are used in:
Electric power generation plants
Steel, oil and chemical industries
Aircrafts, Ship propulsion
Turbo jet and turbo-propeller engines likerockets, missiles, space ships etc.,
29
-
7/28/2019 Turbines 1 Fudamental
30/64
Open cycle gas turbine:
The entire flow of the working substance
comes from atmosphere and is returnedto the atmosphere back in each cycle.
Closed cycle gas turbine:
The flow of the working substance ofspecified mass is confined within the cyclic
path. ( Air or Helium is the workingsubstance)
30
-
7/28/2019 Turbines 1 Fudamental
31/64
COMPRESSOR:
draws in air and compress it before it is fed
into combustion chamber COMBUSTOR:
fuel is added to the compressed air and
burnt to produce high velocity exhaust gas TURBINE:
extracts energy from exhaust gas
31
Open cycle gas turbine
-
7/28/2019 Turbines 1 Fudamental
32/64
32
-
7/28/2019 Turbines 1 Fudamental
33/64
33
-
7/28/2019 Turbines 1 Fudamental
34/64
34
-
7/28/2019 Turbines 1 Fudamental
35/64
35
-
7/28/2019 Turbines 1 Fudamental
36/64
36
-
7/28/2019 Turbines 1 Fudamental
37/64
Open cycle Closed cycle
Lesser thermal efficiency Higher
Loss of working fluid No loss of working
fluid
Bigger in size SmallerBig compressor is needed Smaller one is
sufficient
Possibility of corrosion of blades and
rotor
Free from corrosion
Economical Not economical
Exhaust gases from turbine exit to
atmosphere
Fed back into the
cycle
37
Difference between open & closed cycle turbine
-
7/28/2019 Turbines 1 Fudamental
38/64
PharmaceuticalPharmaceuticalPharmaceuticalPharmaceutical
38
-
7/28/2019 Turbines 1 Fudamental
39/64
HospitalsHospitalsHospitalsHospitals
39
-
7/28/2019 Turbines 1 Fudamental
40/64
Pulp and PaperPulp and PaperPulp and PaperPulp and Paper
40
-
7/28/2019 Turbines 1 Fudamental
41/64
41
-
7/28/2019 Turbines 1 Fudamental
42/64
42
-
7/28/2019 Turbines 1 Fudamental
43/64
It is a prime mover, which converts hydro
power (energy of water)into mechanical
energy and further into hydro-electric
power.
43
C f f
-
7/28/2019 Turbines 1 Fudamental
44/64
Classification of Water TurbinesBased on action of water:
1. Impulse turbine
pelton wheel.2. Reaction turbine francis and kaplan.
Based on name of originator:1. Pelton turbine or Pelton wheel
2. Francis turbine3. Kaplan turbine
Based on head of water:1. Low head turbine
2. Medium head turbine
3. High head turbine
44
-
7/28/2019 Turbines 1 Fudamental
45/64
Pelton Turbine(Pelton Wheel or Free Jet Turbine)
High head, tangential flow, horizontal
shaft, impulse turbine
45
-
7/28/2019 Turbines 1 Fudamental
46/64
46
PELTON TURBINE
-
7/28/2019 Turbines 1 Fudamental
47/64
47Pelton Turbine Runner
-
7/28/2019 Turbines 1 Fudamental
48/64
48
-
7/28/2019 Turbines 1 Fudamental
49/64
Only a part of the pressure energy of
the water is converted into K.E. and
the rest remains as pressure head.
49
Fi t th t t th
-
7/28/2019 Turbines 1 Fudamental
50/64
First, the water passes to the guide
vaneswhich guide or deflect the water
to enter the blades, calledmovingblades, mounted on the turbine wheel,
without shock.
The water from thegu ide bladesare
def lected on to themoving blades,
where i ts part of thepressu re energyis
converted intoK.E., which w i ll be
abso rbed by the turbine wheel . Thewater leaving the moving blades will
be at a low pressure.
50
-
7/28/2019 Turbines 1 Fudamental
51/64
The difference in pressure between the
entrance and the exit of the moving bladesis called React ion pressu re, which acts on
moving blades of the turbine wheel and
sets up the turbine wheel into rotation inthe opposite direction.
Examples:Francis turbine, Kaplan turbine,Propeller turbine, Thompson turbine, Bulb
turbine.
51
-
7/28/2019 Turbines 1 Fudamental
52/64
Francis TurbineMixed flow, medium head reaction turbine.
Consists of a spiral casingenclosing anumber of stationary gu ide bladesfixed allround the circumference of an inner ring of
moving blades (vanes)forming the runner,which is keyed to the turbine shaft.
Radial entry of water along the periphery of
the runnerand discharge at the center of therunner at low pressure through the divergingconical tube called draft tube.
52
-
7/28/2019 Turbines 1 Fudamental
53/64
53
FRANCIS TURBINE
-
7/28/2019 Turbines 1 Fudamental
54/64
54
Francis Inlet Scroll, Grand Coulee Dam
http://en.wikipedia.org/wiki/Image:Francis_Turbine_inlet_scroll_Grand_Coulee_Dam.jpg -
7/28/2019 Turbines 1 Fudamental
55/64
55
Francis Runner,
Grand Coulee Dam
http://en.wikipedia.org/wiki/Image:Francis_Runner_grandcoulee.jpg -
7/28/2019 Turbines 1 Fudamental
56/64
56
FRANCIS TURBINE & GENERATOR
-
7/28/2019 Turbines 1 Fudamental
57/64
57
-
7/28/2019 Turbines 1 Fudamental
58/64
Kaplan TurbineAxial flow, low head.
Similar to Francis turbine except the runner
and draft tube.
The runner(Boss orHub) resembles with the
propeller of the ship, hence some times it is
called as Propel ler tu rbine.
Water flows parallel to the axis of the shaft.
58
-
7/28/2019 Turbines 1 Fudamental
59/64
59KAPLAN TURBINE
(SCROLL CASING)
(GUIDE VANE)
(RUNNER VANE)
-
7/28/2019 Turbines 1 Fudamental
60/64
60
-
7/28/2019 Turbines 1 Fudamental
61/64
61
-
7/28/2019 Turbines 1 Fudamental
62/64
62
Vertical Kaplan Turbine(Courtesy: VERBUND-Austrian Hydro Power)
Propeller Turbine Runner
-
7/28/2019 Turbines 1 Fudamental
63/64
63
Propeller Turbine Runner
-
7/28/2019 Turbines 1 Fudamental
64/64