Effect of rotation number on flow and heat transfer characteristics in serpentine passage with ribbed walls

Abstract

We studied the flow and heat transfer characteristics in a rotating serpentine passage with ribbed walls. The channel length-tohydraulic diameter ratio of the rotating serpentine passage (L/Dh), the rib height-to-hydraulic diameter ratio (e/Dh), rib angle of attack (a), the rib pitch-to-height (p/e) ratio and aspect ratio (AR) were fixed at 11.33, 0.13, 90°, 10 and 1, respectively. Numerical simulations were performed at a constant Reynolds number, Re = 10000. The rotation number (Ro) levels were 0.0, 0.1, 0.2 and 0.3. The distribution of local heat transfer coefficients and the flow field in a rotating serpentine channel were studied by numerical simulations using the commercial software ANSYS ver.15.0 (Fluent). The results show that the local heat transfer at the first-pass trailing and the second-pass leading surfaces has significantly higher rates than at the first-pass leading and second-pass trailing surfaces, due to rotational effects with Coriolis forces that are high in the middle region between two ribs, and very low immediately before and after the ribs. In addition, the overall thermal hydraulic performance with rib-roughened walls was best at the highest rotation number tested (Ro = 0.3).