This document provides an overview of magnetohydrodynamic (MHD) energy and power generation. MHD power generation directly converts the kinetic energy of ionized gases into electricity using the interaction between the moving fluid and a magnetic field, without requiring moving mechanical parts. There are two types of MHD systems - open cycle systems that use the working fluid once and closed cycle systems that continuously circulate and reheat the working fluid, usually helium or argon. MHD generators have efficiencies up to 50-60% and advantages like fewer mechanical parts and losses, but require very high temperatures to ionize gases and have shorter lifetimes for working parts due to thermal stresses.

1. G.L. BAJAJ INSTITUTE OF TECHNOLOGY & MANAGEMENT
Prepared by-
Mr. Vishal Shankar Srivastava
(Asst. Prof.)
Department of Mechanical Engineering
TOPIC - MAGNETOHYDRODYNAMIC ENERGY
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2. Table of Content
 Introduction
 Principle
 Working
 Advantage
 Disadvantage
 Application
 Reference
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3. Introduction
 Magneto hydrodynamic power generation provides a way of generating
electricity directly from a fast moving stream of ionised gases without
the need for any moving mechanical parts - no turbines and no rotary
generators [1].
Or
 Magneto hydrodynamic power generation is a process in which
generate electric power by means of the interaction of a moving fluid
(usually an ionized gas or plasma) and a magnetic field [2].
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4. Working Principle
Fig: (A) Principle of MHD generator working(a,b) (B) MHD
generator[4,2]
 The principal of MHD power generation is very simple and
is based on Faraday’s law of electromagnetic induction.
 An ionized gas move at speed “u” across magnetic field “B.
Two electrode are held perpendicular, whose area is “A” and
distance between electrode is “d”. The interaction of ionized
gas and magnetic field create an electric field “E” at right
angle to “u” and “B”. Due to this a potential difference
generate across the plate and current is generated.
The max. power generated per unit volume is =
𝑃 =
σu2 B2
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Where, u is the fluid velocity, B is the magnetic flux density, σ is
the electrical conductivity of conducting fluid and ρ is the density
of the fluid. [4]
 MHD generator act as a Heat Engine.
 Its efficiency is about 50 – 60% (maximum)
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5. The MHD cycles can be of two types -
1. Open Cycle MHD System
 In this system the working fluid used only once.
 Air is used as a working fluid.
 Gas is seeded with cesium or potassium.[4]
Fig: An open cycle MHD generator[4]
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6. 2. Close MHD Cycle System –
 In close system working fluid continuously
circulated. The working fluid after
generating electricity is reheated and return
to convertor for reuse.
 Helium or argon is used as a working fluid.
 In this heat is transferred from the
combustion gases to the working fluid by
means of heat exchanger.
 Brayton cycle is used for heat conversion.
Fig: A Close cycle MHD generator[4]
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7. Advantages [4]
 Here only working fluid is circulated, and there are no moving
mechanical parts. This reduces the mechanical losses to nil and
makes the operation more dependable.
 Efficiency will be maximum up to 50-60%.
 It has the ability to reach full power level almost directly.
 The price of MHD generators is much lower than conventional
generators.
 MHD has very high efficiency, which is higher than most of the
other conventional or non-conventional method of generation.
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8. Disadvantage [4]-
 It require very high temp. for ionizing the gas.
 Working parts life time is less due to thermal stress and high temperature.
 It require power to maintain magnetic field.
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9. References :
 https://www.mpoweruk.com/mhd_generator.htm
 https://www.britannica.com/technology/magnetohydrodynamic-power-
generator
 https://www.electrical4u.com/mhd-generation-or-magneto-hydro-dynamic-
power-generation/
 NON-CONVENTIONAL ENERGY RESOURCES, By - G.S. Sawhney, PHL
learning publication -2012
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