Convective heat transfer in a channel with perforated ribs

An experimental study of convective heat transfer in a channel implemented with perforated ribs immersed in a turbulent boundary layer is presented. Infrared thermography associated with the steady heated thin foil technique is applied to obtain the mapping of the heat transfer coefficient. Different types of perforations are compared in the case of single turbulator configuration. Conclusions are drawn on the effect of the rib design on the heat transfer enhancement. Next, the study focuses on the turbulator with perforations of chevron type. Then, emphasis is given to the influence of the rib-to-rib spacing, the open-area factor and the channel Reynolds number on the thermal exchange. Compared to solid rib, a local thermal enhancement factor of 3 can be expected just behind the perforated turbulator. Fully developed flow is reached after the 5th to 6th rib. The optimal design combines a rib pitch ratio of 5 with an open area factor of 0.53 for channel Reynolds number ranging from 30000 to 60000. (C) 2002 Editions scientifiques et medieales Elsevier SAS. All rights reserved.