EFFECT OF BLOCKAGE-RATIO ON DEVELOPING HEAT TRANSFER FOR A RECTANGULAR DUCT WITH TRANSVERSE RIBS

摘要

The developing heat transfer characteristics in a rectangular channel (AR = 4) equipped with continuous transverse ribs are experimentally investigated. The ribs were regularly spaced over a section of the channel which was heated by a uniform heat flux. The blockage ratio e/D_h varied from 0.039 to 0.078. Two values of the rib pitch to rib height ratio (10 and 20) were considered, with the Reynolds number from 57,000 to 127, 000. The studied geometry is relevant to turbine structures between high pressure and low pressure turbines in aircraft engines. The maps of local heat transfer coefficient in the inter-rib regions were obtained by using the steady state liquid crystal thermography. The main purpose is to investigate the effect of blockage ratio (e/D_h) on the developing heat transfer behavior. In particular, the heat transfer characteristics between the first repeated ribs, i.e., in the inter-rib regions were studied, where the flow field is fully developed while the thermal field is not yet periodically fully developed.