Insulating wall boundary layer in a Faraday MHD generator
Abstract
Experimental and analytical investigation was undertaken of the insulating wall boundary layer in a Faraday MHD generator. Insulating wall boundary layers show that modifications due to (MHD) effects have significant influence on the insulating wall friction and heat transfer in Faraday MHD generators. Modified flow (Hartmann Flow) is evidenced by an alteration of the velocity profile, due to the variation of the J x B force across the channel in the magnetic field direction. The nonuniform current distribution is related to variations in both the velocity and the electrical conductivity across the channel. The analytic model involved computerized solution, using finite difference techniques, of the momentum, energy, and electrical equations, including MHD effects for the turbulent insulating wall boundary layer. The turbulence model used, was the mixing length theory which was modified to include turbulence damping. Variable, equilibrium properties were employed producing a coupling between the momentum, energy, and electrical equations resulting in extended Hartmann flow. The experimental study consisted of the measurement of the velocity profile at the center of the insulating wall in an MHD generator using a laser anemometer.
 Publication:

NASA STI/Recon Technical Report N
 Pub Date:
 April 1978
 Bibcode:
 1978STIN...7921310R
 Keywords:

 Computerized Simulation;
 Insulation;
 Magnetohydrodynamic Generators;
 Mathematical Models;
 Structural Analysis;
 Turbulent Boundary Layer;
 Walls;
 Current Distribution;
 Damping;
 Electrical Resistivity;
 Finite Difference Theory;
 Hartmann Flow;
 Heat Transfer;
 Laser Anemometers;
 Magnetic Fields;
 Reynolds Number;
 Skin Friction;
 Turbulence Models;
 Velocity Distribution;
 Fluid Mechanics and Heat Transfer