ANALYSIS OF IMPINGEMENT JET HEATING AND COOLING OF THERMOMAGNETIC MATERIAL

In this paper, an experimental study is carried out to investigate the temperature response of a thermomagnetic material subjected to water and air jet impingement. In particular, the thermomagnetic material is included in a heat energy harvesting device that uses water to heat and air to cool. The aim of the study is to enhance heat transfer and identify the limits of jet impingement to control the temperature-dependent magnetic properties of thermomagnetic materials. Beyond the Curie temperature, in fact, the material loses its magnetic properties and becomes paramagnetic. The rapid change in magnetization around the Curie temperature can be used to design a device that converts thermal energy into other useful forms of energy. The study aims to identify the suitable conditions required to operate the device and optimize the time required for heating and cooling of the material. For this reason, time dependent simulations are performed to understand how the temperature on the material varies over time for different values of water temperature and inlet velocity. Moreover, an analysis on the effect of jet impingement exit velocity, nozzle diameter and nozzle-to-surface distance on the heat transfer characteristics is made, showing the variation of the thermal time constant with these parameters.