Second Law Analysis of Hydromagnetic Flow from ...

In this paper, the second law analysis of hydromagnetic conducting flow due to a stretching rotating disk with heat transfer is investigated using a semi-analytical/numerical technique termed DTM-Pade simulation. The study has applications in rotating magneto-hydrodynamic (MHD) energy generators for new space systems and also thermal conversion mechanisms for nuclear propulsion space vehicles. The momentum and energy conservation equations are non-dimensionalized using appropriate transformations leading to a set of nonlinear, coupled, ordinary differential equations for momentum in the radial, azimuthal and normal directions and a temperature distribution equation. Using the appropriate velocity components and temperature field, the entropy generation equation is obtained. The effects of various parameters such as magnetic interaction parameter, rotation parameter, Eckert number, Brinkman number on the entropy generation and Bejan number are illustrated and described. The irreversibility mechanisms of the entropy generation for the emerging parameters are also investigated and suggestions for minimizing the entropy generation are proposed. The DTM-Pade results are verified with the numerical results and found to be in excellent agreement. The simulations also show the feasibility of using magnetic rotating disk drives in novel nuclear space propulsion engines.