06-09-2016, 11:15 AM
1453191626-mhd.pdf (Size: 399.95 KB / Downloads: 33)
ABSTRACT
It is really mortifying to hear the fact that only 30% of the energy from the fuel used reaches
the wheels of a typical automobile implying most of the remaining energy is lost as heat. Since most
of the energy consumed by an internal combustion engine is wasted, capturing much of that wasted
energy can provide a large increase in energy efficiency. So the possibilities of where and how to
capture this lost energy are matters of great significance. Also the situation now existing in internal
combustion engines is that a part of the engine power generated is consumed by the alternator
incorporated in the automobile which leads to an increase in fuel consumption of the engine. So there
persists before us a challenge to come up with a new technique that would help in efficient utilization
of fuel in automobile. The plan opted for was to incorporate an Magneto Hydro Dynamic (MHD)
power generation unit in the exhaust pipe line which actually is a device that converts the energy loss
through exhaust into useful electric power by making use of the Faraday’s effect. This device works
on the basis of magneto hydro dynamic power generation and it is a new unique method of power
generation. Working of this device is by converting thermal energy and kinetic energy of gases into
electrical energy. Externally added ions to the fast moving gases are allowed to pass through an
externally applied magnetic field. This will give rise to generation of electric power on the plates
kept at the sides.
Keywords: Magneto Hydro Dynamics, Exhaust Gas Temperature, Exhaust Gas Heat Recovery,
Magnetic Flux, Gas Velocity.
I. INTRODUCTION
In the last years the rapid rise in the use of electric power has raised the problem how to
provide the power increases. From sector studies the total electrical power consumption has almost
doubled in the last twenty years. The problem of finding appropriate technologies to produce cheap
INTERNATIONAL JOURNAL OF ADVANCED RESEARCH IN ENGINEERING
AND TECHNOLOGY (IJARET)
ISSN 0976 - 6480 (Print)
ISSN 0976 - 6499 (Online)
Volume 5, Issue 3, March (2014), pp. 164-172
© IAEME: www.iaemeijaret.asp
Journal Impact Factor (2014): 7.8273 (Calculated by GISI)
www.jifactor.com
IJARET
© I A E M E
International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online) Volume 5, Issue 3, March (2014), pp. 164-172, © IAEME
165
energy and ensure the right standard of environmental compatibility has in recent years led to an
increase in technological progress. Nowadays electrical energy is the form of energy to which all
other forms of energy may be converted. It is easy to transport, easy to control and easy to transform.
Most of the times, however, energy can be converted into electricity only through many intermediate
transformations, which leads to limitations in efficiency, reliability, and compactness. The critical
point in general in the energy conversion is the combination of heat and mechanical energy of the
conversion system, which limits the maximum temperature involved. To avoid the mechanical
limitations it seems promising to convert directly heat into electricity.
We all know that it is a matter of global concern regarding the depletion of fossil fuels like
petrol, diesel, natural gas etc. because of their extreme need in many of the practical applications
such as in automobiles, aircrafts, power plants, locomotives etc. Especially when dealing with
automobiles, the use of fuels like diesel and petrol for its running is just inevitable. These fuels have
their applications in internal combustion engines of automobiles to derive power required for motion.
But the problem that protrudes out from the studies conducted is that about 70% of the energy
derived from the fuel is lost as heat which implies that only 30% proves beneficial for a vehicle’s
running. Since most of the energy consumed by an internal combustion engine is wasted, seizure of
much of this wasted energy can provide a large increase in energy efficiency. For example, a typical
engine producing 100 kilowatts of driveshaft power expels 68 kilowatts of heat energy through the
radiator and 136 kilowatts through the exhaust. So the prospects of where and how the capture of this
lost energy is accomplishable are matters of great significance. Also the enduring situation in internal
combustion engines of a part of the engine power generated being consumed by the alternator
incorporated in automobile leads to an increase in fuel consumption of the engine. So there persists
before us a challenge to come up with a new technique that would help in efficient utilization of fuel
in automobile.
The strategy adopted was to amalgamate a Magneto Hydro Dynamic (MHD) power
generation unit to the exhaust pipe line, thereby generating electric power which would thus replace
the use of a conventional alternator and hence provide an efficient means of fuel management.
Magneto hydro dynamics is the physical-mathematical framework that concerns the dynamics of
magnetic fields in electrically conducting fluids, e.g. in plasmas and liquid metals. The word
magneto hydro dynamics is comprised of the words magneto- meaning magnetic, hydro- meaning
water (or liquid) and dynamics referring to the movement of an object by forces. Synonyms of MHD
that are less frequently used are the terms magneto fluid-dynamics and hydro-magnetics. Yet an
another factor that is propitious to the proposed methodology is that there are no moving parts
incorporated in this method, thereby energy losses due to friction are next to zero. Hence the MHD
power generation technique considerably has a higher efficiency.
II. WORKING PRINCIPLE
A. Faraday’s Law of Electromagnetic Induction.
Electromagnetic induction is the production of a potential difference (voltage) across a
conductor when it is exposed to a varying magnetic field. Faraday's law of induction is a basic law of
electromagnetism predicting how a magnetic field will interact with an electric circuit to produce an
electromotive force (EMF). It is the fundamental operating principle of transformers, inductors, and
many types of electrical motors, generators and solenoids.
Magneto Hydro Dynamic (MHD) Power Generation
MHD portraits the study of the interaction of magnetic fields and electrically conducting
liquids or gases, such as molten metal or plasma. According to Faraday’s law of electromagnetic
induction, when an electric conductor moves across a magnetic field, a voltage is induced in it which
produces an electric current. In MHD generator, the solid conductors are replaced by a gaseous
conductor, to be specific, an ionized gas. A suitable seed is used to ionize the gas. When this ionized
gaseous conductor is moved so as to cut the lines of magnetic induction, the charged particles in the
conductor experience a force in a direction mutually perpendicular to the magnetic field (B) and to
the velocity of the conductor (V). The negative charges tend to move in one direction, and the
positive charges in the opposite direction. This induced electric field, or motional EMF, provides the
basis for converting mechanical energy into electrical energy. The EMF is perpendicular to both V
and B according to the Fleming’s Right hand rule and induced electromotive force is found out by,
Induced EMF, E = q. (V x B)
Where,
‘q’ is the charge density.
From the relation above it is evident that large EMF is induced, if the applied magnetic flux
density, charge density and gas velocity are high.