PRESENTATION ON KAPLAN

TURBINE

PREPARED BY:GOKARNA BASNET

B.TECH(ME 4TH SEM)

ANSAL UNIVERSITY,GURGAON

Kaplan Turbine

Viktor Kaplan (1876-1934)

INTRODUCTION Invented by Prof. Viktor Kaplan of Austria during 1913 – 1922.The Kaplan is of the propeller type, similar to an airplane propeller.The difference between the Propeller and Kaplan turbines is that the Propeller turbine has fixed runner blades while the Kaplan turbine has adjustable runner blades. The kaplan's blades are adjustable for pitch and will handle a great variation of flow very efficiently. They are 90% or better in efficiency and are used in place some of the old Francis types in a good many of installations. The kaplan turbine, unlike all other turbines, the runner's blades are movable. The application of Kaplan turbines are from a head of 2m to 40m.

Kaplan Turbine

The Kaplan turbine is a water turbine which has adjustable blades and is used for low heads and high discharges.

The Kaplan turbine is an inward flow reaction turbine, which means that the working fluid changes pressure as it moves through the turbine and gives up its energy.

The inlet is a scroll-shaped tube that wraps around the turbine's wicket gate. Water is directed tangentially through the wicket gate and spirals on to a propeller shaped runner, causing it to spin.

  The Kaplan turbine having drop height: 10 - 700 m and Flow rate 4 - 55 m3/s

Kaplan Turbine

Main Parts of a Kaplan Turbine

Scroll Casing:It is the Casing in which guides the water and controlthe water passage.Guide Vanes: It is the blade in which guides the water

and control the water passage. Draft Tube:After passing through the runner the water is discharged to the tail race through a gradually expanding tube.Runner: It is connected to the shaft of the generator.Hub: It is the part of the runner in which blades are mounted.Governing Mechanism:it controls the position of guide

blades to affect the variation of flow rate when load condition chnges.

 

KAPLINE TURBINE

Main components of Kaplan turbine

Major Parts of A Kaplan Turbine

DESIGN OF WHEEL AND RUNNER

Section of Guide Wheel Runner

Essential for High Efficiency at low Heads

Design of Kaplan Runner

Drunner

Dhub

The Kaplan Runner

KAPLAN BLADE

DESIGN OF THE BLADE

Two different views of a blade

Adaptation Mechanism inside the Hub

Working Principle: Water under pressure flush draft tube through the guide vanes and

falls on the adjustable blades,

which enables adjust the flow and makes runner rotating. After crossing propeller is the kinetic energy of water converted

into rotational motion shaft. The shaft powered generator

producing electric power.

Operation of kaplan turbine The water from the penstocks enters the scroll casing and then

moves to the guide vanes.

From the guide vanes, the water turns through 90° and flows axially through the runner.

For Kaplan Turbine, the shaft of the turbine is vertical. The lower end of the shaft is made larger and is called ‘Hub’ or ‘Boss’.

The vanes are fixed on the hub and hence Hub acts as runner for axial flow turbine.

The peripheral velocity velocity u of the runner vanes depends upon the radius of the point under consideration & thus the blade angle vary from the rim to the boss & the vanes are wraped,this is necessary to ensure shock free entry &exit.

Classification of Kaplan Turbines The Kaplan turbine can be divided in double and single

regulated turbines. A Kaplan turbine with adjustable runner blades and

adjustable guide vanes is double regulated while one with only adjustable runner blades is single regulated.

The advantage of the double regulated turbines is that they can be used in a wider field.

The double regulated Kaplan turbines can work between 15% and 100% of the maximum design discharge;

the single regulated turbines can only work between 30% and 100% of the maximum design discharge.

Velocity triangles and work done per second:1.work done per second;=ρQ[Vw1U1] {∵Vw2 =0} 2.work done per second per unit weight of water striking=Vw1U1/g

3.Hydraulic eff.(�h)=Vw1U1/gH

4.Mechanical eff.(�m)=SP/RP5.Overall eff.(�o)=SP/WP

Vf2

Vr2

U2

Vf1

V1

Vw1

U1

Vr1

For Kaplan turbine U1 = U2

Vf1 = Vf2 Also ß =900

because of radial flow at outlet. Vf2=V2 &Vw2=0

ø

α θ

Fig: Velocity Diagram

Characteristic curves of Kaplan turbine:

Main Characteristic curves of a Kaplan turbine

Fig: unit discharge vs unit speed curve

Main Characteristic curve of Kaplan turbine

fig: unit power vs unit speed fig: overall eff.vs unit speed

Advantages: It can be used for the sites having very low Head.

The advantage of the double regulated turbines is that they can be used in a wider field.

At part loads there is reduced loss of efficiency.

Kaplan turbine has efficiency up to 90 percent

Because of small dimension of the power house

there is saving in excavation and civil Engineering works.

The frictional loss is less because of less number of blades.

Disadvantages: Leakage of water into generator chamber and Condensation

are source of trouble.

Cost is very high for maintenance.

Applications:Kaplan turbines are widely used throughout the world for electrical power production. They cover the lowest head hydro sites and are especially suited for high flow conditions.Inexpensive micro turbines on the Kaplan turbine model are manufactured for individual power production with as little as two feet of head.Large Kaplan turbines are individually designed for each site to operate at the highest possible efficiency, typically over 90%. They are very expensive to design, manufacture and install, but operate for decades.