mhd generators
TRANSCRIPT
MAGNETO HYDRODYNAMIC
GENERATORS
PRESENTED BY
NITHIN GOPAL
CONTENTS
1 . Introduction
2 . Brief Story
3 . Principles Behind
4 . Construction
5 . Working
6 . Classifications
6 . M.H.D Systems
7 . Merits and Demerits
8 . Applications
9 . Contents taken from…
INTRODUCTION Energy produced from the conventional methods is not sufficient for the daily use because of energy
crisis is on its maximum level.
So , more energy must be produced by non conventional methods of energy production.Magneto hydro dynamics is dynamics of electrically-conducting fluids and their interactions with magnetic field.
M.H.D generator is a new non conventional power generation system which has high efficiency and low pollution.
BRIEF STORY
o It was Michael Faraday who first discussed about M.H.D generators in 1832.
o First international conference on M.H.D power in1962.
o First M.H.D generator was found in 1965.
o At the beginning of 70s,interest in MHD declined because nuclear power was becoming more widely available.
o In 1975, UNESCO became persuaded the MHD might be the most efficient way to utilise world coal reserves .
o By 1994, Russia had developed and operated the coal-operated facility .
PRINCIPLES BEHIND
The main principles behind M.H.D generators are:
1.FARADEY’S LAW OF ELECTRO MAGNETIC INDUCTION.
2.‘LORENTZ FORCE LAW.
FARADAY’S LAW OF ELECTRO MAGNETIC INDUCTION
When a conductor is placed in a changing magnetic field , an E.M.F is induced in that conductor.
LORENTZ FORCE LAW
A charged particle moving through a magnetic field experiences a force that is at right angles to both the direction in which the particle is moving and the direction of the applied field.
F=Q .(v*B)
CONSTRUCTION
Linear MHD channel (front view):-
Linear MHD channel (side view):-
Wall assembly of the disc MHD channel:-
Components of disc MHD generator:-
Components of the ionized seed injection system:
WORKING
WORKING
Classifications
According to the construction, it can be classified into four:
1. Faraday generator
2. Hall generator
3. Diagonal generator
4. Disc generator
Faraday generator
Hall generator
Diagonal generator
Disc generator
M.H.D. POWER GENERATING SYSTEM
An M.H.D power generating system consists of the following parts:
1.Heater
2.M.H.D generator
3.Cooler
4.Compressor
Simple block diagram of a M.H.D system
CLASSIFICATIONS OF M.H.D SYSTEMS
M.H.D systems
Open cycle system
Closed cycle system
Seeded inert gas system
Liquid metal system
Open cycle system
In open cycle system ,oil or gasified coal may used as fuel.
The fuel is burnt in the combustor and the hot gases from the combustor is then mixed with a small amount of an ionized alkali metal (cesium or potassium) to increase the electrical conductivity of the gas.
OPEN CYCLE SYSTEM
Closed cycle system In this system , instead of
directly feeding the burnt gas is into the generator , a heat exchanger is used to transfer the heat from combustor to the generator.
According to the medium used to transfer the heat, this system is broadly classified into two.
1. Seeded inert gas system
2. Liquid metal system
Seeded inert gas system
This system uses inert gases as energy carriers from heat exchanger to the generator . Some ionized materials are seeded into the carrier as in the open cycle system.
Seeded inert gas system
Liquid metal system
Here the carrier is liquified metal . Usually Sodium is used as the working fluid .This directly induces the E.M.F into the generator . So no seeding is needed.
Liquid metal system
MERITS OF M.H.D GENERATORSHigh efficiency as compared to
steam power plants.
Large amount of power is generated.
No moving parts .
Closed cycle produces less pollutants.
It can be started instantaneously.
Much smaller sized plant can be used.
Direct conversion of heat into electricity is happened.
Solar energy also can be used for producing heat.
DEMERITS OF M.H.D GENERATORS
Since the generator works at very high temperature, the materials used for the construction must withstand high temperature.
Pollution cannot be neglected.
Less efficient than Hydro power generation.
Seed materials attack the insulation.
High capital cost.
APPLICATIONS
o They are used in large scale power production for industrial and domestic applications.
o Is used in space applications like power production in Rockets , Space ships etc.
CONTENTS TAKEN FROM…Non conventional energy sources-G .D . Rai
www.ehow.com
www.wikipeadia.com
www.electropedia.com
www.buzzle.com
Renewable sources of energy – M.Rrjalingam
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