Date post: | 14-Jun-2015 |
Category: |
Education |
Upload: | spondan-bora |
View: | 4,521 times |
Download: | 2 times |
HYDRAULIC TURBINES AND ITS CLASSIFICATION
SPONDAN S. BORA
DefinitionHydraulic Turbine is a prime mover that
uses the energy of flowing water and converts it into the mechanical energy in the form of rotation of runner wheel.
Also termed as ‘water turbines’.
Flow sheet of hydroelectric power plant
ClassificationBased on hydraulic action of waterBased on direction of flowBased on head of water and quantity of flowBased on specific speedBased on disposition of turbine shaftBased on name of originator (commonly used
turbines)
Based on hydraulic action of water
Impulse turbine : One in which all the energy of water is converted to kinetic energy before the water strikes the vanes of the runner wheel. This is done by passing the flow through nozzle or some guidelines. The runner is rotated by the force of water and water passes over the wheel at atmospheric pressure.
Ex- Pelton Wheel
Impulse Turbine
Reaction Turbine : Here, water entering the runner wheel of the turbine has both kinetic energy and pressure energy that is total head of water striking the runner wheel ,consist partly of pressure head.
E.g- Francis turbine, Propeller turbine, Kaplan turbine
Reaction Turbine (Kaplan Turbine)
Based on direction of flow Radial flow turbine : A radial flow turbine is a turbine in
which the water as it move along the vane flow towards the axis of rotation or away from it.
Radial flow turbine is of two types:I. Inward flow turbine : If the flow of water is towards the
axis of rotation, its called inward flow turbine.II. Outward flow turbine : If the flow of water is away from
the axis of rotation , its called outward flow turbine.
Radial Flow Turbine
Axial flow turbine : Its the turbine in which water enters the runner wheel parallel to the direction of axis of rotation of runner.
Ex- Kaplan turbine, Propeller turbineTangential flow turbine : Its the turbine in which
water strikes the runner wheel tangentially to the path of rotation.
Ex- Pelton turbine
Axial Flow Turbine
Mixed flow turbine : It’s the turbine in which the direction of flow is partly radial and partly axial. Water enters the blade radially and comes out axially parallel to the turbine shaft.
Based on head of water and quantity of flowHigh head turbine : when head is above 250 mEx- Pelton wheelMedium head turbine : when head is between 60m – 250mEx- Francis turbineLow head turbine : When head is between 15-60 mEx- kaplan turbineVery low head turbine: When is head is less than 15mEx- Propeller turbine
Based on specific speedSpecific speed Types of turbine
10-35 Pelton wheel with one nozzle35-60 Pelton wheel with two or more
nozzle, Multi jet pelton wheel60-300 Francis turbine
300-1000 Kaplan turbine
Based on disposition of turbine shaftTurbine shaft may be either vertical or
horizontal. Pelton turbine usually have horizontal shafts whereas the rest have vertical shafts.
Based on name of originator Pelton wheel : Tangential flow impulse turbine
used for high head of water.Francis turbine : Inward flow reaction turbine used
for medium head of water.Kaplan turbine : Axial flow adjustable blades
reaction turbine used for low head of water.Propeller turbine : Fixed blades axial flow reaction
turbine used for very low head of water.
Francis TurbinePropeller TurbineKaplan Turbine
THANK YOU