Numerical simulation and design of a thermomagnetic motor

• We modeled a thermomagnetic motor.
• We compared the performance of this motor using three materials (two magnetocaloric materials).
• We designed a thermal machine, which source of energy is solar.

The increasing demand for energy has driven society to explore different energy sources, seeking to achieve sustainability. In this sense, we have focused to design a rotary motor using solar power with similar working principle as a Curie wheel. This paper describes the modeling, simulation and design of a Curie thermomagnetic motor. Three materials were analyzed for the rotor, out of which two of them present a second order phase transition a 30% FeNi alloy and Gd, and the MnAs that presents a first order transition. In addition, the heat transfer inherent to the conversion process of solar energy and natural convection were studied utilizing a one-dimensional finite difference model, and the best performance for the assumed initial conditions for the motor for all materials was with a convention coefficient of 10 W/(m2 K). A model for the magnetic circuit was also developed. It could be verified that Gd and MnAs offers about one order of magnitude more power when compared to 30% NiFe alloy. An experimental bench engine prototype was also designed, but not built, utilizing the same parameter values and considerations applied to the simulation, in order to fit it with the mathematical model. Moreover, a cylindrical concave mirror and mechanism was designed to harness the needed solar energy, which can be adjusted to keep incident solar rays always perpendicular to the mirror.