Hydro Power

5/27/2018 Hydro Power

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INTRODUCTION TO HYDRO POWER

SYSTEM

ASSIGNMENT 1


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What is a turbine?

A turbine is a rotary mechanical device that

extracts energy from a fluid flow and converts

it into useful work, namely electricity.

A turbine is a turbo machine with at least one

moving part called a rotor assembly, which is a

shaft or drum with blades attached. Moving

fluid acts on the blades so that they move andimpart rotational energy to the rotor.


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Turbine Blade


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Classification of turbines based on

working fluid:

When the working fluid is water turbines arecalled hydraulic turbines or hydroturbines.

When working fluid is air, and energy is extracted

from the wind, the machine is called windturbine.

When the working fluid is steam, turbines arecalled steam turbines.

A more generic name for turbines that employ acompressible gas as the working fluid is gasturbines.


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hydraulic turbines or hydroturbines


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Wind turbine

For wind velocity measurement

For power generation


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Wind turbine


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Wind turbine

1. Computer systems control the direction ofturbine blades to match the direction of thewind

2. Wind pushes turbine blades into rotation3. Blades turn a generator to convert

mechanical energy into electricity

4. Generator sends electricity throughtransmission lines to the power grid, bringingelectricity to homes and businesses


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Steam turbines


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Steam turbines

A Typical CHP System Turbine or Engine with Heat Recovery Unit


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Gas turbines

Working of a Gas Turbine to generate electricity


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TYPES OF EFFICIENCIES

Depending on the considerations of input and

output, the efficiencies can be classified as

(i) Hydraulic Efficiency

(ii) Mechanical Efficiency

(iii) Overall efficiency


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Hydraulic Efficiency

If R.P. is the Runner Power and W.P. is the

Water Power

=

.

.


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Mechanical Efficiency

If S.P. is the Shaft Power and R.P. is the Runner

Power.

=

.

.


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Overall Efficiency

=


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Major reaction turbines used in

hydropower plant

Impulse turbines turn the generator by depending onthe change in velocity of water jet. The direction ofwater flow is altered when the jet stream of water ispushed on the curved blades of impulse turbines. The

resulting change in momentum i.e. impulse produces arotational force on the blades and thus pushes thegenerator. Meanwhile, the stream flow out turbine willexperience decrease in energy as its involved in therotational effect of turbine. The transfer of energy for

impulse turbines is governed by Newtons Second Lawof Motion where the impulse produced will diminishwith the turning of turbine (Sharma, 2011)


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For Reaction Turbines; it rely more on thepressure changes in pushing the turbines.Therefore, the reaction turbine such as Francis

turbine is commonly installed in a fullysubmerged condition. The pressure drop (headlosses) between the inflow and outflow of waterstream will drive the movement of rotating

blades within the submerged reaction turbine.This phenomenon is governed by Newtons ThirdLaw of Motion (Sharma, 2011).


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It can be concluded that impulse turbines are

more depending on the kinetic energy that

generates from water flow, while reaction

impulse utilise both the kinetic energy andpressure drops caused by water flow. Thus,

impulse turbine often involved in high head

application while reaction turbine is moreconvenient in medium and low head

application.


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PELTON WHEEL


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Features of Pelton Wheel

High head and low dischargeAdvantage of Pelton Wheel is very suitable for power

extraction, when water energy is available in the high headand low flow rate. Pelton turbine is a high head impulseturbine and had been use for high head and low flow rate

applications.

Control mechanism: nozzle and deflectorNozzle: Nozzle will help to increase velocity of jet

further. This will be a good tool or aid in effectiveproduction of impulse force.

The important feature is the power production as thejet is deflected (Pelton Turbine Experiment, N/A, p.1). Therole of deflector is to control the turbine speed.


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Why Pelton Wheel is an impulse

turbine? The function of this turbine is to convert fluid energy to mechanical energy.

According to Pelton Turbine Experiment, Pelton Wheel is a water impulse turbinebecause it converts the water head through a nozzle into a high-velocity jet,which then strikes the buckets at one position as they pass by.

The important value of this impulse turbine is zero reaction (R=0).

Bukaba Micro-Hydro Power Plant used the highest head installations of Pelton

Wheel. This cause come from desire to develops an efficiencies closely to theFrancis reaction Turbine.

Pelton turbine is used for high head application. Usually between 100 to 1000m. Italso used for low flow hydro applications.

Impulse Pelton Wheel extracts energy from the impulse of water movement, asopposed to its weight. High speed water jet injected through a nozzle hits bucketsof Pelton wheel. It influence an impulsive force and that force makes the turbine

rotate. When it shaft runs a generator; produces electricity. Easy to handle e it have only

one turbine stage. This turbine is very suitable for high head and relatively lowpower.


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References

HOW WIND ENERGY WORK(2014) Retrieved from http://www.greenmountain.com/resources/enviro-kids/renewable-energy-101/wind energy

Hydraulic Turbines(n.d.) Retrieved from http://www.ustudy.in/node/537

Prakash M.N.S (n.d) Hydraulics and Hydraulic MachinesRetrieved from http://elearning.vtu.ac.in/P6/enotes/CV44/Pel_Whe-MNSP.pdf

Robertson, J.A. and Crowe, C.T. (1993). Engineering Fluid Mechanics, 5th edition, Houghton

Mifflin, Boston, MA. Sharma, G. (2011). Turbine - a rotary engine. Impulse, 7, 9. Retrived from

http://www.itmindia.edu/images/ITM/pdf/impulse%20sep%202011/Turbine%20 %20A%20Rotary%20Engine.pdf.

STEAM TURBINES(2014) Retrieved from http://www.luminant.com/responsibility/education/generation/steam.aspx

TECHNICAL GUIDANCE(2013) Retrived from http://connect.scenetwork.co.uk/tech_guide.php

White, F.M. (1994). Fluid Mechanics, 3rd edition, McGraw-Hill, Inc., New York, NY.

University of Lowa. (N/A). Pelton Turbine Experiment. Retrieved March 3, 2014, fromhttp://www.engineering.uiowa.edu/~cfd/pdfs/53-071/lab4.pdf


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Thank you

Hydro Power

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