Heat transfer analysis of the baking system for EAST

Abstract

Before long-pulse plasma operation, wall conditioning is addressed as a key element to achieve steady state long-pulse operation with high performance, which is one of the major challenges for EAST (Experimental Advanced Superconducting Tokamak). The vacuum vessel and in-vessel components are continuously heated with hot nitrogen for a few weeks, namely the baking process, and the beginning of wall conditioning. It is difficult to accurately predict the specific temperature distribution of the baking system in the baking process under the current analysis and experimental conditions. Therefore, a simplified calculation model has been established in this paper, which is helpful to reveal the dynamic response mechanism and the heat loss to guide the input power of the baking system. The heat transfer relationship has been given by the theoretical method, and the calculation results of two cases are obtained by using Matlab/Simulink. The results gained by the heat transfer model were compared with the actual experimental data, which verified the correctness of the model. This heat transfer calculation model can be used in the future EAST experiment to predict the baking system operation behavior.