Studies on a cooling of high heat flux surface in fusion reactor by impinging planar jet flow

Abstract

Divertor surface of a fusion reactor is exposed to strong surface heating by high flux charged particles. According to typical design of ITER, the heat flux on divertor surface becomes locally near 20 MW m −2. Then, it is necessary to establish a cooling method to cool such high heat flux surface. A cooling by a planar impinging jet has been proposed. However, in the application of the impinging jet cooling to flat heated surface, high CHF is obtained in the limited region near center. As apart from the region, CHF decreases abruptly with a distance from the center. To overcome this difficulty, we proposed that an impinging planar jet was applied to a concave heated wall where a flow induced centrifugal force acts effectively along the curved surface. In a previous paper, we investigated the CHF for a free planer jet on the concave surface. In this study, CHFs in a confined planar jet, were investigated as a function of distance from the center in the various subcooling, flow velocity and curvature of cooling surface and compared with the CHF in the free planar jet cooling. To investigate CHF in the abnormal condition like mild plasma disruption, CHFs in the transient power input were investigated and discussed in comparison with the steady state CHF. Finally application by both impinging planar jets to the divertor surface are discussed.