1938, U.S scientist Bela Karlovitz introduced
the Magneto hydrodynamic generation
The Magneto hydrodynamic (MHD) generator is
a device that converts thermal energy of a fuel
into electrical energy.
80 % of total electricity produced in the world is
hydal, while remaining 20% is produced from
nuclear, thermal, solar, geothermal energy and
from magneto hydro dynamic (mhd) generator.
The word magneto hydro dynamics (MHD) is
derived from magneto-meaning magnetic
field, and hydro-meaning liquid, and dynamics meaning movement. Hannes
Alfvén worked a lot on MHD generation , for
which he received the Nobel Prize in Physics
Magneto hydrodynamics (MHD) is
the academic discipline which studies
the dynamics of electrically
Examples of such fluids include plasmas,
liquid metals, and salt water.
MHD generator, the solid conductors are
replaced by a gaseous conductor, an
ionized gas. If such a gas is passed at a
high velocity through a powerful magnetic
field, a current is generated and can be
extracted by placing electrodes in suitable
position in the stream.
The principle can be explained as follows.
“An electric conductor moving through a
magnetic field induces electric field and
MHD generator consist of a Combusion chamber and generator
The fliud conductor is passed into the combusion
where they are ionized at very high temperature.
There is a nozzel through which the ionized gas pass into the
The generator chamber consist of powerful magnet and a
number of oppositely located electrode pair is inserted in the
channel to conduct the electrical current generated to an
Both combusion chamber and generator chamber are suurounded
by a heat resistance material and water cooler
The gaseous (fluid) conductor is passed into the
combustion chamber through inlet.
By using a fuel like oil (or) natural gas (or) coal, the
fluid conductor is heated to a plasma state and
hence it is ionized.
The temperature in the combustion chamber is
around 2000°K to 2400°K.
The heat generated in the combustion chamber
removes the outermost electrons in the fluid
Therefore, the gas particle acquires the charge
charged gas particles with high velocity
enters into the generator chamber via
positive and negative charge moves to
constitute the current.
direction of current is perpendicular to
direction of moving gas
particle and to the magnetic field.
The electrodes are connected to an
external circuit to get a load output.
The current produced in the
generator are direct current (DC)
This DC current can be converted into
alternative current (AC) using an inverter
attached with the external circuit.
The on and off time is about second.
There are no moving parts, it is very reliable to
The MHD generator has high thermal efficiency
It is a direct conversion device.
They have a better fuel utilization
It can produce large amount of power
The size of the pant is small
They need high pure superconductor.
Working temperature is very high as about
200°K to 2400°K.
The loss of power if very high
The components get high corrosion due to
high working temperature.
The MHD generators are used to power
submarines and aircrafts.
They are used in rocket for space application
They can be used as power plants in industry
and uninterrupted power supply system