Analysis and Design of a Novel Permanent Magnet Uniform Magnetic Field Generator

Magnetic fields are utilized as one of the nonthermal methods for food processing and preservation, and numerous studies have demonstrated their effectiveness in enhancing food quality. The effects of magnetic fields on food quality are highly inconsistent in terms of magnetic field intensity and the type of applied fields, suggesting a potential “window” effect. However, most studies only describe the magnetic field on the surface of the magnet or the average intensity of a certain part of the sample, which hinders both drawing correct conclusions about the synergy produced by the programmed combination of physical agents and achieving an optimal design of the processing device. To address this issue, the present study presents a comprehensive analysis and design of an innovative permanent magnet (PM) uniform magnetic field generator specifically designed for application in refrigerators to preserve food. An analytical model is derived for the PM uniform magnetic field generator to accurately calculate the distribution of the generated magnetic field. The design parameters of the magnetic field generator were then optimized using the genetic algorithm, and its performance was compared with that of the conventional magnetic field generator. Finally, a prototype of the novel PM uniform magnetic field generator has been manufactured and tested, increasing the size of the uniform magnetic zone by over 60% compared with the conventional structure. As a result, a larger range of “accurate” magnetic field environment is provided for the food inside the refrigerator.