Affiliations: [a] EFD Induction GmbH, Freiburg im Breisgau, Germany | [b] Institute of Electrotechnology, Leibniz Universität Hannover, Hannover, Germany
Abstract: In high performance induction heating systems, the coil often has a short lifetime as a result of high power density generated in some areas. The cause of life reduction is often because the cooling effect of the coolant is not sufficient or the heat is not dissipated adequately. This is usually due to a poor heat transfer between the cooling water and the coil. The sizing of the cooling system and the coil have a high impact on the heat transfer and therefore also on service life. Generally, the system parameters affected by this dimensioning are the cooling water temperature, cooling water flow (velocity) and pressure. In this paper, a method is presented which allows a research of the influences by these different parameters on the heat transfer coefficient. For this purpose, a water-cooled, cylindrical copper part is heated by induction and the heat transfer to the coolant is examined. Considering that, a concept has been developed and analyzed by means of a 2D model. This is followed by the implementation of the model using an experimental setup, where an individual adjustment of the three cooling parameters has been realized and also its impacts on the heat transfer coefficient.
Keywords: Induction heating, convective heat transfer coefficient, lifetime of coils
