Experimental and Numerical Investigation of the Thermal Performance of the Gas-Cooled Divertor Plate Concept

The helium-cooled plate-type divertor concept proposed by Malang was designed to accommodate a surface heat load of ~10 MW/m². This design can potentially reduce the number of modules needed for the divertor by over two orders of magnitude compared with other concepts, thereby significantly reducing coolant delivery system complexity and manufacturing costs. While previous analyses have predicted that the plate design can accommodate heat fluxes of 10 MW/m², no experimental data have been published to date to validate such analyses. Experiments have therefore been conducted using air as the coolant at Reynolds numbers similar to those proposed for the actual helium-coolant operating conditions on an instrumented test module with cross-sectional geometry identical to the prototypical plate-type divertor. A second test module where the planar jet exiting the inlet manifold is replaced by a two-dimensional hexagonal array of circular jets over the entire top surface of the inlet manifold has also been tested. The thermal performance of both test modules with and without a porous metallic foam layer in the gap between the outer surface of the inlet manifold and the cooled surfaces was directly compared to test the numerical simulations of Sharafat which predict that the metallic foam significantly enhances heat transfer.