Flexible circulated-cooling liquid metal coil for induction heating

Induction heating is well-established as a technique to provide fast, contactless and efficient heating of conductive materials, where the induction coil is of key importance for inductive power transfer. This paper reports on a novel flexible liquid metal coil (LMC) for induction heating system through adopting liquid metal as current-carrying conductor and circulated-cooling fluid, respectively, which could be dynamically remodeled as needed to a variety of coil geometries for adapting to the workpiece shape. A novel LMC structure, composing of two connected silicone tubes filled with circulated-cooling liquid metal, was designed to prevent the alternating current flow into cooling system. The experiment and simulation results demonstrated that the circulated-cooling liquid metal could effectively inhibit the temperature rise of LMC induced by eddy-current losses, which only lead to a small temperature raise of 0.39 °C for flow rate of 1 ml/s and coil losses of 1 W. In addition, impacts of the LMC size, flow speed and the loaded current on the LMC temperature were investigated in detail. A liquid metal multiple-channel structure was also developed to significantly reduce the coil losses of LMC to its 32.6%. The present study opens the way for further development of LMC applications in inductive power transfer.