Experimental and numerical investigation of a full-scale helium-cooled divertor finger mock-up

A modular helium-cooled divertor design based on the multi-jet impingement concept (HEMJ) that is capable of accommodating a surface heat flux of at least 10 MW/m2 has been developed at the Forschungszentrum Karlsruhe. Experimental investigations with a full-scale mock-up designed and built at the Georgia Institute of Technology, Atlanta were carried out in the helium loop HEBLO at Karlsruhe. Tests were run at heat loads of up to 2 MW/m2 and flow conditions of 38 °C and 8 MPa so that the Reynolds number matches that for the actual divertor operating conditions (∼21,600). Comparison between the experimental data and results of simulations performed using the computational fluid dynamics code ANSYS CFX showed good agreement for the cooled surface temperature distribution, while the pressure loss was underestimated by about 20% by the code.