Turbo machine content

1. MEC 803 POWER ENGINEERING
AY 2022-23
Course Coordinator:Mr Raahul Krishna
Department of Mechanical Engineering
Module 05: Hydraulic Turbines
Topic: Reaction Turbines (Kaplan Turbine)
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5. Contents
CO5: Estimate performance parameters and efficiencies for impulse and reaction
turbines.
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6. Features of Reaction Turbines
i. Only part of the overall pressure drop has occurred up to turbine
entry, the remaining pressure drop takes place in the turbine itself;
ii. The flow completely fills all of the passages in the runner, unlike the
Pelton turbine where, for each jet, only one or two of the buckets at a
time are in contact with the water;
iii. Pivotable guide vanes are used to control and direct the flow;
iv. A draft tube is normally added on to the turbine exit; this is
considered as an integral part of the turbine.

7. Comparison of Impulse and Reaction
Turbine

8. Comparison of Francis and Kaplan Turbine

9. Mixed Flow and Axial Flow Kaplan Turbines

10. Kaplan Turbine
 The Kaplan turbine is a great development of early 20th century.
 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.
 It is a pure axial flow turbine uses basic aerofoil theory.
 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 (but
great) Francis types in a good many of installations.
 They are very expensive.
 In 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.

11. Kaplan turbines
 Low head (from 70 meter and
down to 5 meter)
 Large flow rates.
 The runner of a Kaplan turbine
resembles with propeller of a
ship, hence also known as
propeller turbine.
 The runner vanes can be
governed
 Good efficiency over a wide
range

12. The five-bladed propeller of a Kaplan
turbine used at the Warwick hydroelectric
power station in Cordele, GA. There are
five runner blades of outer diameter 12.7
ft (3.87 m). The turbine rotates at 100 rpm
and produces 5.37 MW of power at a
volume flow rate of 63.7 m3/s from a net
head of 9.75 m.

13. Design of Kaplan Runner
Drunner
Dhub

15. A Kaplan turbine produces 60,000 kW under a net head of 25 m with an overall
efficiency of 90%. Taking the value of speed ratio as 1.6, Flow ratio as 0.5 and the
hub diameter as 0.35 times the outer diameter, find the diameter and speed of the
turbine.

17. The following data pertain to a Kaplan Turbine: Power available at shaft = 22500
kW, Head = 20 m, Speed = 150 rpm, Hydraulic Efficiency = 95%, Overall Efficiency
= 88%. Outer diameter = 4.5 m, Diameter of the hub = 2 m. Assuming that turbine
discharges without whirl at exit, determine the runner vane angles at the hub and
at the outer periphery.