Heat/mass transfer characteristics in angled ribbed channels with various bleed ratios and rotation numbers

The present study investigates the effects of secondary flow due to angled rib turbulators the heat/mass transfer in the square channels with channel rotation and bleed flow. The angle of attack of the angled ribs was 45 deg. The bleed holes were located between the rib turbulators on either the leading or trailing surface. The tests were conducted under the conditions corresponding to various bleed ratios (BR=0.0, 0.2, and 0.4) and rotation numbers (Ro=0.0, 0.2, and 0.4) at Re = 10,000. The results suggest that the heat/mass transfer characteristics were influenced by the Coriolis force, the decrement of the main flow rate, and the secondary flow. In the 90 deg angled ribbed channel, the heat/mass transfer reduced on the leading surface with an increment in the rotation number, but it increased on the trailing surface. However, it decreased on both surfaces in the 45 deg angled ribbed channel. As the bleed ratio increased, the Sherwood number ratios decreased on both the bleeding and nonbleeding surfaces for the 45 deg angled ribs but increased on the bleeding surface for the 90 deg angled ribs.