Experimental and Numerical Investigation of Thermal Performance of Gas-Cooled Jet-Impingement Finger-Type Divertor Concept

As a part of the ARIES study, a modular, helium-cooled, jet-impingement, finger-type divertor design that can accommodate an incident heat flux of 10 MW/m² has been proposed. An experimental and numerical investigation was undertaken to quantify the thermal performance of a design that closely resembles previously studied finger-type divertors (e.g. HEMJ and HEMP). Experiments were conducted using air in a test module heated with an oxy-acetylene torch to achieve incident heat fluxes as great as 2 MW/m². These experimental results were compared to numerical predictions.

The numerical studies documented here were performed using a commercial computational fluid dynamics (CFD) software package. Simulations were carried out for two different test sections with and without a hexagonal array of cylindrical fins and otherwise identical dimensions and for two different flow directions, reverse flow corresponding to radial inward flow, and forward flow corresponding to jet impingement followed by radial outward flow. The numerical predictions for effective heat transfer coefficients (HTC) are in reasonable agreement with the experimental results for the test section without fins. The numerical predictions overpredict the HTCs for the cases with fins, and resolving this discrepancy is the subject of ongoing work.