Numerical Simulation and Experimental Validation of Internal Heating in Vacuum Pressure Impregnation Process for High Field Coil

An experimental system has been built to explore the vacuum pressure impregnation (VPI) technique and internal heating method. The mold with coil and support part is put into the vacuum tank and a novel type of epoxy resin IR-3 is applied for impregnation. The heat transfer models is built to simulate the heating process and calculate the radiation heat leakage and heating power. A shield is made to reduce the radiation heat leakage and two preliminary experiments without impregnation are carried out to verify the thermal insulation effect of the radiation shield. An experiment with impregnation and shield is carried out to identity the temperature rise, the magnitude of current and heating power applied to the coil. The numerical and experimental results showed that the radiation heat leakage is the main way of heat loss during curing process, and the shield can reduce radiation heat leakage effectively, thereby heating power consumption is reduced, meanwhile the coil and resin could not reach the setting temperature when shield is absent. The results obtained in this article will helpful to manufacture superconducting coils using VPI technique and internal heating method.