The effect of increasing Hartmann number and duct wall conductivity on the incompressible laminar flow of a liquid metal (Pb-17Li) in a rectangular duct under a transverse magnetic field has numerically been studied using usual equations of fluid dynamics coupled with the electromagnetic equations of the appropriate form. Simulations have been performed for ducts with and without electrical insulation, and the pressure drop is evaluated in each of the cases. The results of the simulation are compared with the analytical relations found in the literature. Finally, the applicability of different insulation coatings vis-à-vis their effect in reducing the magnetohydrodynamics pressure drop has been examined. Index Terms-Hartmann number, magnetohydrodynamics (MHD) flow, test blanket module (TBM).

The electric potential near a wall for a multi-species plasma with volume produced negative ions in presence of axially varying magnetic field is studied following an analytical-numerical approach. A constant negative ion source is assumed throughout the plasma volume, along with finite temperature positive ions and Boltzmann electrons. The particles are assumed to be guided by an open magnetic field that has its maximum at the centre, and field strength decreasing towards the walls. The one dimensional (1D) Poisson equation is derived using an analytical approach, and then solved numerically to study the potential profiles. Effect of (a) negative ion production rate, (b) magnetic field profile, and (c) negative ion temperature on the potential profile has been investigated. A potential peak appears near the wall when the negative ion temperature and density are sufficiently high. Also, the presence of negative ions further decreases the potential in the plasma region for a finite Debye Length (λD).

No abstract

No abstract

Two-dimensional modeling of non-transferred dc plasma torches have been performed using an axis symmetric geometrical configuration and boundary conditions. A control volume approach and SIMPLER algorithm is used to solve the governing equations for mass, momentum, and energy conservation coupled with the electric and magnetic fields. The results are compared with the ones obtained in 3-D simulation works of the authors. Results show substantial difference in control parameters as calculated from the two simulations, owing to local attachment of the arc over the anode surface.Index Terms-DC plasma torch, non-transferred plasma torch, thermal plasma.