Department of Instrumentation & Control Engineering
CLASIIFICATION OF HYDRAULIC TURBINE
KAPLAN AND PROPELLER TURBINE
SOME RELATED TERMS DEFINATION
EFFICIENCIES OF HYDRAULIC TURBINE
GOVERNING OF HYDRULIC TURBINE
SELECTION OF TURBINE
Machines which convert hydraulic energy(energy
possessed by water) into mechanical energy are
A hydraulic turbine converts the potential energy of
water into mechanical energy which in turn is utilised
to run an electric generator to get electric energy
Water wheels have been used for thousands of years
for industrial power.
The word turbine was introduced by the French
engineer Claude Bourdin in the early 19th century
and is derived from the Latin word for "whirling" or a
The main difference between early water turbines and
water wheels is a swirl component of the water which
passes energy to a spinning rotor.
i. Head and quantity of water available.
ii. Name of the originator.
iii. Action of water on the moving blades.
iv. Direction of flow of water in the runner.
v. Disposition of the turbine shaft.
vi. Specific speed NS.
• Requires high head and small quantity of flow
• Requires low head and high rate of flow.
i. Head and quantity of water
• Lester Allen Pelton of California (USA)
• James Bichens Francis
• Dr. Victor Kaplan
ii. Name of the originator
iii. Action of water on the moving
• Pelton turbine
Tangential flow turbine
Radial flow turbine
• Kaplan turbine
Axial flow turbine
iv. Direction of flow of water in the
• Francis turbine
Mixed flow turbine
Pelton have horizontal shaft.
Francis, Kaplan have vertical shaft.
v. Disposition of the turbine shaft.
vi. Specific Speed NS
• Speed of a turbine, identical in shape,
geometrical dimensions, blade angles etc., with
actual turbine but with such a size that it’ll
develope unit horse power when working under
• Specific Speed, NS = (N √P )/ H5/4
Where, N= Normal working Speed in rpm
P= Power output of the turbine
H= net or effective heads in meters
The specific speed for various type of runners are given below:
Type of turbine Type of runner Specific speed
10 to 20
20 to 28
28 to 35
60 to 120
120 to 180
180 to 300
Kaplan - 300 to 1000
Consists of rotor , at the peripery of which, double-
hemispherical or elliptical buckets are mounted.
It is a tangential flow impulse turbine.
A Pelton’s runner consists of a single wheel mounted
on a horizontal shaft.
Pelton type Specific
12- 30 89% 2000
2 nozzle 17-50 89% 1500
4 nozzle 24- 70 89% 500
Nozzle: It controls the amount of water striking the
vanes of the runner.
Casing: It is used to prevent splashing of water and
plays no part in power generation.
Runner with buckets: Runner is a circular disc on
the periphery of which a number of evenly spaced
buckets are fixed.
Breaking Jet: To stop the runner in short time
breaking jet is used.
Main Parts of a Pelton Wheel
Water falls towards the turbine through a pipe called
penstock and flows through a nozzle.
The high speed jet of water hits the buckets (vanes)
on the wheel and causes the wheel to rotate.
A spear rod which has a spear shaped end can be
moved by a hand wheel.
The change in momentum of water stream produces
an impulse on the blades of the wheel of Pelton
It is an inward-flow reaction turbine that combines
radial and axial flow concepts.
Vertical shaft may also be used for small size
turbines, but normally they have horizontal shaft.
Francis type Specific
Low 250-400 93% 30-60
Medium 150-250 93% 50-150
High 80-150 93% 500
CASING: The runner is completely enclosed in an air-
tight spiral casing. The casing and runner are always full
GUIDE MECHANISM: Water is fall down to the
turbine and passed through the no’s of stationary orifices
fixed all around the circumference of the runner , this is
called guide vanes . The guide vanes allow the water to
strike the vanes of the runner without shock at inlet
RUNNER: It is a circular wheel on which a series of
curved radial guide vanes are fixed.
DRAFT TUBE: It is used for discharging water from the
outlet of the runner to the tail race.
Main parts of a Francis Turbine
In addition to electrical production, they may also be
used for pumped storage, where a reservoir is filled
by the turbine (acting as a pump) during low power
demand, and then reversed and used to generate
power during peak demand.
The Kaplan turbine is a propeller-type water turbine
which has adjustable blades.
The runner of a kaplan turbine resembles with
propeller of a ship. That is why, a Kaplan turbine is
also called as propeller turbine.
KAPLAN AND PROPELLER
Efficiency Head (in
340-1000 93% 10-60
Bulb 1000-2000 91% 3- 9
Kaplan Turbine Runner
The turbine wheel, which is completely under water,
is turned by the pressure of water against its blades.
Guide vanes regulate the amount of water reaching
The Kaplan turbine is the most widely used of the propeller-type turbines,
but several other variations exist:
Propeller turbines have non-adjustable propeller vanes.
Bulb or Tubular turbines are designed into the water delivery tube. A large
bulb is centered in the water pipe which holds the generator, wicket gate
and runner. Tubular turbines are a fully axial design, whereas Kaplan
turbines have a radial wicket gate.
Pit turbines are bulb turbines with a gear box. This allows for a smaller
generator and bulb.
Straflo turbines are axial turbines with the generator outside of the water
channel, connected to the periphery of the runner.
S- turbines eliminate the need for a bulb housing by placing the generator
outside of the water channel. This is accomplished with a jog in the water
channel and a shaft connecting the runner and generator.
VLH turbine an open flow, very low head "kaplan" turbine slanted at an
angle to the water flow. It has a large diameter, is low speed using a
permanent magnet alternator with electronic power regulation and is very
fish friendly (<5% mortality). VLH Turbine
Tyson turbines are a fixed propeller turbine designed to be immersed in a
fast flowing river, either permanently anchored in the river bed, or attached
to a boat or barge.
Inexpensive micro turbines on the Kaplan turbine
model are manufactured for individual power
production with as little as two feet of head.
Kaplan turbines are individually designed for each
site to operate at the highest possible efficiency,
typically over 90%.
S.No. Scheme/Project Location (State) Source of water
1. Bhakra- Nangal project
2. Hirakud dam project Hirakud (orissa) Mahanadi river
3. Nizam Sagar project
INSTALLATION IN INDIA
Francis turbine versus Pelton turbine:
(i) Mechanical efficiency of Pelton decreases faster
with wear than Francis.
(ii) Size of powerhouse required is small and
economical if Francis is used than Pelton.
(iii) Cavitation is an ever present danger in Francis.
(iv) The water hammer effect is more trouble in
(v) In Francis , variation in the operating head can be
Kaplan versus Francis turbine:
(i) Kaplan is more compact.
(ii) Part load efficiency is high.
(iii) Low frictional losses in Kaplan.
Cavitation: Cavitation is the formation of empty
cavities in a liquid by high forces and the immediate
implosion of them.
Cavitation occurs when a liquid is subjected to rapid
changes of pressure causing the formation of cavities
in the lower pressure regions of the liquid.
Prof. Dietrich Thoma of Munich (Germany)
suggested a factor ,called cavitation factor.
SOME RELATED TERM’S
Methods to avoid cavitation:
(i) Runner/turbine may be kept under water.
(ii) Cavitation free runner may be designed.
(iii) By selecting materials that can resist better the
(iv) By polishing the surfaces.
(v) By selecting a runner of proper specific speed for
The runaway speed of a water turbine is its speed at
full flow, and no shaft load.
The practical values of run away speeds for various
turbines with respect to their rated speed N are as
Pelton Wheel …1.8 to 1.9N
Francis turbine (mixed flow) …2.0 to 2.2N
Kaplan turbine (axial flow) …2.5 to 3.0N
(i) Hydraulic efficiency, is ratio of power developed
by the runner of a turbine to the power supplied by
the water at the inlet.
(ii) Mechanical efficiency, ratio of power available at
the shaft to power developed at the runner.
(iii) Volumetric efficiency, ratio of volume of the water
actually striking the runner to the volume of water
supplied to the turbine.
(iv) Overall efficiency, ratio of power available at the
shaft of the turbine to the power supplied by the
water at the inlet of the turbine.
Efficiencies of a turbine
The draft tube is a pipe of gradually increasing area
which connects the outlet of the runner with the
It creates a negative head at the outlet of the runner
thereby increasing the net head on the turbine.
It converts a large proportion of rejected kinetic
energy into useful pressure or potential head.
Two types of draft tube:
(i) Canonical type: used on low powered units for all
specific speeds, frequently, on large head units.
(ii) Elbow type: used to turn the water from the vertical
to horizontal direction with minimum depth of
excavation and with high efficiency.
Means speed regulation
Governing of Impulse turbine:
(i) Spear regulation.
(ii) Deflector regulation.
Governing of Reaction turbine
Part load operation.
Disposition of turbine Shaft.
SELECTION OF TURBINE
On overall discussion , we can conclude that
generation of electricity by hydraulic turbine is best
way of restricting pollution and no fuel required,
although we must be particular about the site.
We can also conclude Kaplan and propeller is best