Heat transfer characteristics in two-pass rib-roughened channel at high rotation number with different channel angles

To match the real engine operating condition, Reynolds number and rotation number range of current experiment were expanded from 10000 to 70000 and 0 to 2.08 by increasing the air pressure. Experiment was conducted to investigate the heat transfer characteristics in a square two-pass channel with inclined 45 degree ribs, and three different channel angles (0 degree, 22.5 degree, 45 degree) were selected to study the effect of channel angle on heat transfer characteristics. Results indicate that in the first channel, channel angle has a larger effect on trailing wall than leading wall, especially near the inlet of the channel; in the second channel, channel angle has a smaller effect on both trailing wall and leading wall. To the region average heat transfer distribution, the 45 degree channel is higher than other channels (0 degree, 22.5 degree), and 0 degree channel is the lowest.