Kaplan Turbine• The Kaplan turbine is a greatdevelopment of early 19thcentury.• Invented by Prof. Viktor Kaplanof Austria during 1913 – 1922.• The Kaplan is of the propellertype, similar to an airplanepropeller.• Kaplan turbine is a low headturbine and used for heads ofless than 80 meters.• It is a pure axial flow turbineuses basic aerofoil theory.
Main Parts of a Kaplan TurbineScroll 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 waterpassage.Draft Tube:After passing through the runner thewater is discharged to the tail racethrough a gradually expanding tube.Runner:It is connected to the shaft of thegenerator.Hub:It is the part of the runner in whichblades are mounted.
Working Principle:• Water under pressure flush drafttube through the guide vanes andfalls on the adjustable blades,which enables adjust the flow.• After crossing propeller is thekinetic energy of water convertedinto rotational motion shaft.The shaft powered generatorproducing electric power.
Classification of kaplan Turbine:• The Kaplan turbine can be divided in double and singleregulated turbines.• A Kaplan turbine with adjustable runner blades andadjustable guide vanes is double regulated while one withonly adjustable runner blades is single regulated.• 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% and100% of the maximum design discharge.
Advantages:• It can be used for the sites having very low Head.• The advantage of the double regulated turbines is thatthey 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 housethere is saving in excavation and civil Engineering works.
Disadvantages:• Leakage of water into generator chamber andCondensation are source of trouble.• Cost is very high for maintenance.