A PRESENTATION ON MAGNETO HYDRO DYNAMICS (MHD)

SYSTEM

Contents1. Introduction2. Need of MHDs3. Principle Of MHD Power Generation4. Types of MHD SYSTEM5. Open Cycle MHD System6. Closed Cycle MHD System7. Diffrence between Open Cycle and

Closed Cycle MHD System8. Advantages OF MHD System9. Disadvantages of MHD System10. Applications11. Conclusion

Introduction Magneto HydroDynamic (MHD) system is a

non- conventional source of energy which is based upon Faraday’s Law of Electromagnetic Induction, which states that energy is generated due to the movement of an electric conductor inside a magnetic field.

Concept given by Michael Faraday in 1832 for the first time.

MHD System widely used in advanced countries. Under construction in INDIA.

Need of MHDs

At present a plenty of energy is needed to sustain industrial and agricultural production, and the existing conventional energy sources like coal, oil, uranium etc are not adequate to meet the ever increasing energy demands. Consequently, efforts have been made for harnessing energy from several non-conventional energy sources like Magneto Hydro Dynamics(MHD) System.

Principle Of MHD Power GenerationFaraday’s law of electromagnetic induction :

When an electric conductor moves across a magnetic field, an emf is induced in it, which produces an electric current.

Lorentz Force on the charged particle (vector),

F = q(v × B) where,• v = velocity of the particle

(vector)• q= charge of the particle

(scalar)• B = magnetic field (vector)

Comparison between a Turbo generator and a MHD generator

Types of MHD SYSTEM

(1)Open cycle System

(2)Closed cycle System

OPEN CYCLE MHD SYSTEM

HYBRID MHD STEAM PART OPEN CYCLE

CLOSED CYCLE MHD SYSTEM

DIFFERENCE BETWEEN OPEN CYCLE AND CLOSED CYCLE SYSTEM

Open Cycle System • Working fluid after generating

electrical energy is discharged to the atmosphere through a stack .

• Operation of MHD generator is done directly on combustion products .

• Temperature requirement : 2300˚C to 2700˚C.

• More developed.

Closed Cycle System • Working fluid is recycled to the

heat sources and thus is used again.

• Helium or argon(with cesium seeding) is used as the working fluid.

• Temperature requirement : about 530˚C.

• Less developed.

NEED FOR FURTHER RESEARCH

The MHD channel operates on extreme conditions of temperature, magnetic and electric fields .

So, numerous technological advancements are needed prior to commercialization of MHD systems .

Search is on for better insulator and electrode materials which can with stand the electrical, thermal, mechanical and thermo-chemical stresses and corrosion.

ADVANTAGES OF MHD SYSTEM

• Conversion efficiency of about 50% .• Less fuel consumption.• Large amount of pollution free power generated .• Ability to reach full power level as soon as started. • Plant size is considerably smaller than

conventional fossil fuel plants .• Less overall power generation cost.• No moving parts, so more reliable .

DISADVANTAGES OF MHD SYSTEM

• Suffers from reverse flow (short circuits) of electrons through the conducting fluids around the ends of the magnetic field.

• Needs very large magnets and this is a major expense.

• High friction and heat transfer losses.• High operating temperature.• Coal used as fuel poses problem of molten ash

which may short circuit the electrodes. Hence, oil or natural gas are much better fuels for MHDs. Restriction on use of fuel makes the operation more expensive.

APPLICATIONS

• Power generation in space craft.

• Hypersonic wind tunnel experiments.

• Defense application.

CONCLUSION

The MHD power generation is in advanced stage today and closer to commercial utilization. Significant progress has been made in development of all critical components and sub system technologies. Coal burning MHD combined steam power plant promises significant economic and environmental advantages compared to other coal burning power generation technologies. It will not be long before the technological problem of MHD systems will be overcame and MHD system would transform itself from non- conventional to conventional energy sources.

REFERENCES• S. Smolentsev, N. Morley, M. Abdou, MHD and Thermal Issues of the

SiCf/SiC Flow Channel Insert, Fusion Science and Technology, 50, 107-119 (2006).

• S. Cuevas, S. Smolentsev,M. Abdou, Vorticity Generation in Localized Magnetic Fields, Magnetohydrodynamics, 42, 199-206 (2006).

• S. Smolentsev, N.B. Morley, M. Abdou, R. Munipalli, R. Moreau, Current Approaches to Modeling MHD Flows in the Dual Coolant Lead Lithium Blanket, Magnetohydrodynamics, 42, 225-236 (2006).

• S. Cuevas, S. Smolentsev, M. Abdou, Vorticity Generation in the Creeping Flow Past a Magnetic Obstacle, Physical Review E, in press, (2006).

• S. Cuevas, S. Smolentsev, M. Abdou, On the Flow past a Magnetic Obstacle, Journal of Fluid Mechanics, 553, 227-252 (2006).

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