Abstract
Morphological effect of a susceptor on Joule heat by induction heating was investigated. Numerical computation of Joule heat was based on mutual inductance model suggested by Tarapore and Evans. The calculated results were compared with experimental results. In experiment, susceptors were made of stainless steel or graphite with two shapes: cylinder-type (Phi 40, or 50 mm X 80 mm) and tube-type (Phi 50 x 80 mm). These were put on the center of a coil and then, their Joule heats were experimentally measured by a specific apparatus using water flow rate and temperature difference. Magnetic field is canceled out by eddy current in cylindrical stainless steel, whereas penetrated to the inside of tubular stainless steel. The calculated values corresponded well to the observed values, within error range of less than 5%. When maximum current of 1A was imposed into the coil, the cylindrical susceptor (Phi 40 mm x 80 mm, stainless steel) placed at middle of the coil generated Joule heat of 9.1 x 10^-3 W/A2 , higher than that of 5.4 x 10^-3 at both ends of the coil. The graphite also showed the same tendency as stainless steel. With a decrease in thickness of the tubular susceptor, heat generation increased because inductive reactance effect deceased and current density became much higher. The tubular stainless steel (Phi 50 mm x 80 mm, t/delta = 0.1) had extremely high heat generation (5.3 x 10^-2 W/A2), matching up to the experimental results. As a result, tubular susceptor heating may compensate various industrial melting systems for large energy consumption, as well as induction furnace.
