Two-phase computational fluid dynamics analysis of a hypervapotron heatsink for ITER first wall applications

3D CFD analysis of subcooled flow boiling heat transfer with hypervapotron configurations for ITER first wall designs

“…Under the anticipated operating conditions, because the flow remains highly subcooled (>100 • C) the process for nucleation, lift-off and subsequent condensation occurs over milliseconds [8,9] [9], one would expect a bubble lift-off diameter of less than 1 mm and its lifetime < 1 ms. Nevertheless, a co-author has estimated an average vapor volume fraction of 6% in the hypervapotron cavity under the heated area with 5 MW/m 2 [5]. Current calculations use the Bergles and Rosenow nucleate boiling prediction procedure [10] for heat transfer as the subcooled boiling heat transfer enhancement models.…”

“…The hypervapotron uses internal water cooling along with a series of fins and cavities perpendicular to the flow to maximize the heat transfer capability. However, under such high heat flux conditions, the surface reaches the incipient boiling temperatures of the water, which results in both boiling in the fluid at adjacent to the fin and a large enhancement of heat transfer [1][2][3][4][5][6]. Thus, the design of the hypervapotron for ITER FW application requires the determination of heat transfer in the subcooled boiling regime.…”