SUMMARY

As a part of the ARIES-CS compact stellarator power plant study, a modular, helium-cooled, T-tube divertor design that can accommodate a peak heat load of 10 MW/m2 has been proposed. Detailed analyses have been performed using the FLUENT® CFD software package to evaluate the thermal performance at the nominal design and operating conditions. Extremely high heat transfer coefficients (>40 kW/(m2-K)) have been predicted. An experimental investigation has been undertaken to validate the results of the numerical simulations. A test module which closely simulates the geometry of the proposed He-cooled T-tube divertor has been tested using air as the coolant while maintaining the same non-dimensional parameter ranges as the He-cooled T-tube divertor design. Axial and azimuthal variations of the local heat transfer coefficient have been measured over a wide range of operating conditions. The experimental data closely match the model predictions. The results of this investigation show that the model can be used with confidence in future design analyses of the T-tube divertor, as well as similar types of gas-cooled high heat flux components. Similar experimental studies will be performed using an alternate divertor geometry. A helium-cooled multi-jet (HEMJ) modular ”finger” configuration with jet impingement cooling from perforated endcaps has been proposed as the lead divertor design for the post-ITER demonstration reactor. A test section that simulates the ‘finger’ design has been designed and constructed. Similar to the T-tube experiment, air will be used as the coolant while maintaining the same non-dimensional parameters of the proposed He-cooled divertor design. This research work will contribute to the understanding and prediction of the performance of the leading proposed He-cooled divertor designs for near- and long-term MFE reactor designs. The results will be used to validate state-of-the-art CFD codes used to model high heat flux plasma-facing components.