hydraulic turbines
DESCRIPTION
hydraulicTRANSCRIPT
HYDRAULIC TURBINES
INTRODUCTION
General layout of a hydro-electric power plant
TAIL RACE
TURBINE
VANES
hf
PENSTOCK
HEAD RACE
DAM
GRO
SS H
EAD
Hg
NET
HEA
D
NOZZLE
Net Head H= Hg-hf
hf = Head lost due to friction
INTRODUCTION
EFFICIENCIES OF A TURBINE
1. Hydraulic Efficiency
Defined as the ratio of power delivered to the runner to the power supplied by the water at inlet of the turbine.
Ξ·h=πππ€ππ πππππ£πππππ‘π hπ‘ πππ’ππππ
πππ€ππ π π’ππππππππ‘ πππππ‘
π π’ππππ πππ€ππ (π .π )=π Γ[π π’1Β±π π’2]Γπ’
πΓ1000πΎπ
πππ€ππ π π’ππππππππ‘ πππππ‘ (π .π )=πΓπΓπΓh
1000πΎπ
INTRODUCTION
EFFICIENCIES OF A TURBINE
2. Mechanical Efficiency
Defined as the ratio of power at the shaft of the turbine to the power delivered by water to the runner.
Ξ·π=πππ€ππ ππ£πππππππππ‘ hπ‘ π hπ πππ‘ ππ hπ‘ ππ‘π’πππππ(π .π )πππ€ππ πππππ£ππππππ¦ hπ‘ ππ€ππ‘ππ π‘π hπ‘ πππ’ππππ (π .π )
3. Volumetric efficiency
Defined as the ratio volume of water actually striking the runner to the volume of water supplied to the turbine.
Ξ·π£=ππππ’ππππ π€ππ‘ππ π π‘ππππππ hπ‘ πππ’ππππ
ππππ’ππππ π€ππ‘ππ π π’πππππππ‘π hπ‘ ππ‘π’πππππ
INTRODUCTION
EFFICIENCIES OF A TURBINE
4. Overall Efficiency
Defined as the ratio of power available at the shaft of the turbine to the power supplied at inlet of the turbine.
Ξ·h=πππ€ππ ππ£πππππππππ‘ hπ‘ π hπ πππ‘ ππ hπ‘ ππ‘π’πππππ(π .π )
πππ€ππ π π’ππππππππ‘ πππππ‘ (π .π )= ππΓπΓπΓh
1000
Ξ·h=π .πΓπ .ππ .πΓπ .π
Ξ·h=Ξ·πΓΞ·h
INTRODUCTION
CLASSIFICATION OF HYDRAULIC TURBINES
Based on energy available:
1. Impulse turbine 2. Reaction turbine
Based on direction of flow through runner
1. Axial flow 2. Radial flow 3. Mixed flow turbines 4. Tangential flow turbines
All energy at the inlet is converted to kinetic
energy before the jet hits the vane
IMPULSE TURBINE REACTION MACHINE
Both pressure and kinetic energy exists when the fluid strikes the vanes.
Based on head available at the inlet
1. High head turbine 2. Medium head turbine 3. Low head turbine
PELTON WHEEL
PELTON WHEEL
A pelton wheel is a impulse turbine. Named after an American engineer L. A. Pelton
COMPONENTS OF A PELTON WHEEL 1. Nozzle and flow regulating arrangement
3. Runner with buckets (double hemispherical cup or bowl)
2. Penstock
5. Breaking Jet
4. Casing
FRANCIS TURBINE - RADIAL FLOW REACTION TURBINE
INTRODUCTION
β’ In radial flow machines, water flows in a radial
direction.
β’ If water flows from inwards to outwards, it is
called a outward flow reaction turbine
β’ If water flows from outward to inward, it is
called as an inward flow reaction turbine.
A Francis turbine is a inward flow reaction turbine having a radial discharge at outlet
COMPONENTS
β’ CASING
β’ GUIDE MECHANISM
β’ RUNNER
β’ DRAFT TUBE
KAPLAN TURBINE- AXIAL FLOW REACTION TURBINE
WORKING
GOVERNING OF A PELTON TURBINE