Detailed Measurement of Convective Heat Transfer in Rotating Two-Pass Rib-Roughened Coolant Channels

The objective of the study is to investigate, through experiments, heat transfer characteristics in a rotating two-pass rib-roughened coolant channel with a sharp 180-deg turn. Detailed measurements of local surface temperatures of the coolant channel are conducted using a newly designed and constructed test section which has as many as 458 thermocouples installed on the rotating channel walls. Description of this unique experimental rig is given. The cross section of the channel is rectangular with 15 mm in width and 30 mm in height. In addition to a rib-free (smooth) surface, two types of rib configurations are employed: 90° and 45° parallel ribs. The measured temperature distribution for the entire test section are shown and the effects of rib configuration and rotation on the cooling performance are examined. It was also found that the secondary flow created in the bend has substantial influence on the heat transfer in the channel after the turning section.