The MHD system
MHD generator :
MHD generators (MHD electrical power generators) are devices in which, according to the magnetohydrodynamics laws, a conversion of the energy of working fluid into electrical energy takes place.Magnetohydrodynamic 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.The principle of operation of MHD generators as well as conventional electrical generators is based on Faraday's induction law.
working principle :
The MHD generator can be considered to be a fluid dynamo. This is similar to a mechanical dynamo in which the motion of a metal conductor through a magnetic field creates a current in the conductor except that in the MHD generator the metal conductor is replaced by a conducting gas plasma.
When a conductor moves through a magnetic field it creates an electrical field perpendicular to the magnetic field and the direction of movement of the conductor. This is the principle, discovered by Michael Faraday, behind the conventional rotary electricity generator. Dutch physicist Antoon Lorentz provided the mathematical theory to quantify its effects.
The flow (motion) of the conducting plasma through a magnetic field causes a voltage to be generated (and an associated current to flow) across the plasma , perpendicular to both the plasma flow and the magnetic field according to Fleming's Right Hand Rule
Lorentz Law describing the effects of a charged particle moving in a constant magnetic field can be stated as
F = QvB
F is the force acting on the charged particle
Q is charge of particle
v is velocity of particle
B is magnetic field