Optimization of the Water-Cooled Structure for the Divertor Plates in EAST Based on an Orthogonal Theory

An orthogonal experimental scheme was designed for optimizing a water-cooled structure of the divertor plate. There were three influencing factors: the radius R of the water- cooled pipe, and the pipe spacing L 1 and L 3 . The influence rule of different factors on the cooling effect and thermal stress of the plate were studied, for which the influence rank was respectively R > L 1 > L 3 and L 3 > R > L 1 . The highest temperature value decreased when R and L 1 increased, and the maximum thermal stress value dropped when R, L 1 and L 3 increased. The final optimized results can be summarized as: R equals 6 mm or 7 mm, L 1 equals 19 mm, and L 3 equals 20 mm. Compared with the initial design, the highest temperature value had a small decline, and the maximum thermal stress value dropped by 19% to 24%. So it was not ideal to improve the cooling effect by optimizing the geometry sizes of the water-cooled structure, even worse than increasing the flow speed, but it was very effective for dropping the maximum thermal stress value. The orthogonal experimental method reduces the number of experiments by 80%, and thus it is feasible and effective to optimize the water-cooled structure of the divertor plate with the orthogonal theory.