Optimization of channel for helium cooled DEMO first wall by application of one-sided V-shape ribs

Helium gas as a coolant offers several advantages in terms of safety. However the use of standard smooth cooling channel surfaces are limited regarding the cooling of high heat flux components in fusion power reactors. Based on our previous assessments, a round-edged, one-side-ribbed rectangular channel was chosen as the baseline geometry, with the ribbed-side facing the plasma-facing wall. This paper presents the optimization of the V-shaped ribbed channel by means of CFD simulations. Thus the effects of the rib pitch, rib angle and channel height are studied. The main criteria for assessing the results are the heat transfer coefficient which determines the maximum wall temperature and, the friction factor which determines the pumping power. The results are also compared with the standard transversal ribbed channel and smooth channel. (C) 2015 Karlsruhe Institute of Technology. Published by Elsevier B.V. All rights reserved.