Magnetically Localizing Heat or Enhancing Equilibration in a Quasi 1D Magnetic Fluid

Abstract

Using two different configurations of temperature and magnetic field gradients, we observed that, in a quasi one-dimensional magnetic fluid, magnetic force either reduces the temperature difference across the sample when the two gradients are parallel to each other (PL), or increase the temperature difference when the two gradients are antiparallel (AP), where the single convection roll in zero field was replaced by two localized flows at the two ends of the sample cell. This flow structure stops the heat flow of approaching to thermal equilibrium in the system, causing the temperature at hot side of the sample cell getting hotter and cold side becoming colder. None of these phenomena can be described by the existing theories of magnetically-induced instabilities. The underlying physics for observed results for AP configuration has been proposed as the mechanism to drive a new type of heat engines that has much higher efficiency than Carnot engines and has no pollution to the environment, our results point to the potential feasibility of this proposed mechanism.