18-12-2010, 02:19 PM
MHD_generator.ppt (Size: 1.32 MB / Downloads: 874)
Presented by:Nikita Khatooa
MAGNETOHYDRODYNAMIC (MHD) GENERATOR
CONTENTS
INTRODUCTION
WHAT IS MHD?
APPLICATION OF MHD TO PLASMA
STRUCTURES IN MHD SYSTEMS
MHD GENERATOR
PRINCIPLE OF OPERATION
TYPES
CONSTRUCTION
EFFICIENCY AND ECONOMICS
ADVANTAGES AND DISADVANTAGES
CONCLUSION
INTRODUCTION
Is the production of electrical power utilizing a conducting plasma through an intense magnetic field
It is a Direct Energy Conversion system.
Are classified based on the nature of processing of the working fluid
Plays an important role in power industry
What is MHD?
MHD: MagnetoHydroDynamics
Otherwise known as Magnetofluiddynamics or Hydromagnetics
Study of dynamics of electrically conducting fluids
The field of MHD was initiated by Hannes Alfven in 1970
Cannot treat kinetic phenomena
Combination of various differential equations describe MHD
Ideal and Resistive MHD
MHD simulation of the solar wind
Ideal MHD: fluid treated as perfect conductor
Resistive MHD: magnetized fluid has finite electron diffusivity
Application of MHD to plasmas
Plasma: It is typically an ionized gas, consists of free electric charges, responds strongly to electromagnetic field
Ideal MHD is applicable in the stricter sense when:
> plasma is strongly collisional
> resistivity due to these collisions is small
> system is smooth and slowly evolving
Structures in MHD Systems
Schematic view of the different current systems which shape the Earth's magnetosphere
MHD Generator
Transforms thermal energy or kinetic energy directly into electricity
They can operate at high temperatures
Have no moving parts
It permits an older single cycle fossil fuel power plant to be upgraded to higher efficiency.
Principle of Operation
The operation is based on the simple principles of Lorentz Force Law.
Products of combustion of fossil fuels, noble gas, liquid metal are used as the working fluid
Maintenance of a very high temperature is required
Types of MHD Generators
According to the working fluid and the anticipated heat source:
i. Open Cycle MHD Generators
ii. Closed Cycle MHD Generators
iii. Liquid Metal MHD Generators
Considering the various MHD Generator designs:
i. Faraday Generator
ii. Hall Generator
iii. Disc Generator
Efficiency and Economics
Closed cycle MHD generator recorded 20% efficiency
Open cycle MHD generator recorded nearly 17% efficiency
Combined with conventional steam plant, up to 60% efficiency recorded
MHD generators for fossil fuels are inherently expensive
Advantages:
i. Increase in the conversion efficiency
ii. Because of higher efficiency overall generation cost is less
iii. Better fuel utilization
iv. Improved environmental effects
v. Better peak power applications and emergency service
Disadvantages
Simultaneous presence of high temperature and a highly corrosive and abrasive environment
MHD channel operates under extreme conditions of electric and magnetic field
Initial installments are expensive
Conclusion
The extensive use of MHD can help in saving billions of dollars towards fuel prospects of much better fuel utilization. The potential of lower capital costs with increased utilization of invested capital provides also a very important economic incentive. The beneficial environmental aspects of MHD are probably of equal or even greater significance. It simultaneously assures better utilization for our natural resources. It can therefore be claimed that the development of MHD for electric utility power generation is an objective of national significance.
References
www.google.co.in
www.wikipedia.com
www.answers.com
www.ieeexplore.ieee.org
www.techsearch.htm