Multiphysics Analysis of a Thermo Acoustic MHD Inductive Generator

This paper fits in the multi-physics analysis of an innovative conceptual design of Magneto-Hydrodynamic (MHD) inductive generator, coupled with a Thermo-Acoustic (TA) resonator. The thermo-acoustic effect occurs when an intense gradient of temperature is present along the axial direction of a duct containing a gas. Such effect allows the heat to be statically converted into mechanical energy of vibration. If the gas is ionized and the charges of opposite sign are separated into two clouds, an alternate electric current is associated to the thermo-acoustic vibration. That current, in its turn, can induce an electromotive force into a magnetically coupled coil. In this way, a thermo-electric conversion is performed, without solid moving parts or matter transport. A FEM analysis has been performed to assess the suitability of the complete energy transformation chain. In particular, the possibility that the charge carriers are involved in the vibration motion is investigated. An acoustic analysis has been done, in a glass tube containing a ionized gas, in order to study the velocity profiles within the duct in presence of viscous and thermal effects. Then, a multiphysics simulation has been performed by using the same geometry, by coupling the acoustic module with the electrostatic module, and the particle tracing module, in order to study the behavior of the unbalanced charge carriers when they are subject to a vibration and to an electric force, for a given set of design parameters.