Heating Characteristics of a HTS DC Induction Heater for Aluminum Billets

The heating process of aluminum billets requires controllable temperature distributions and high efficiency. Compared with conventional ac induction heaters, the high temperature superconductor (HTS) dc induction heater has advantages of energy saving and better heating quality. In this paper, a HTS magnet is designed to achieve controllable temperature distribution for dc induction heater. A C-shaped iron yoke is used to separate HTS coils and billets. An aluminum billet is rotated in the air gap of the C-shaped magnet. Magnetic field distribution can be changed through adjusting width of the air gap. Therefore, the temperature gradient in axial direction is controllable. A dc induction heater prototype using this design is fabricated and its heating characteristics are tested. A numerical model is built to simulate heating process and temperature distributions of aluminum billet. Various uniform and gradient temperature distributions of a billet are measured and compared with numerical results.