Pressure drop and mass transfer in two-pass ribbed channels

Influence of duct aspect ratio on heat/mass transfer in coolant passages with rotation

“…However, the present data are much higher in the turning region and in the upstream region of the second-pass due to different experimental conditions and geometry of the turning region. The results of Chandra and Han (1989) and Liou et al (2002) in Fig. 6(b) show the same trend as the present data.…”

“…Specific experimental conditions are presented in Table 1. The results obtained by Chandra and Han (1989), Liou and Chen (1999) and Mochizuki et al (1999) in Fig. 6(a) show practically the same heat transfer characteristics as the data of the present investigation.…”

“…6(b) show the same trend as the present data. However, the result of Chandra and Han (1989) is generally higher heat transfer due to different experimental conditions of Re = 30,000 and e/D h = 0.063 and the result of Liou et al (2002) is also higher in the turning region because rectangular rib turbulators are installed in the middle of the turn. Fig.…”

“…According to the results, the reattachment distance is insensitive to the rib pitch ratios, Reynolds numbers and roughness heights. Chandra and Han (1989) studied combined effects of sharp turn and rib configuration on mass transfer experiments in stationary square channels, employing various rib geometries that comprise rib height-to-duct hydraulic diameter ratios (e/ D h = 0.063), rib pitch-to-height ratios (p/e = 10) and rib angles-of-attack (90°or 60°). Acharya et al (1997) measured the flow field and thermal field for a flow in a periodically ribbed duct at the transitional flow and the fully turbulent flow.…”

Heat transfer and pressure drop in a smooth and ribbed turn region of a two-pass channel

“…Han et al [26] found that the turn surface for smooth and ribbed channels has an average heat transfer augmentation factor of 1.8 and 2.5 compared to that in the inlet channel, respectively. In the two-pass channel, it is found that the combination of rib arrangements and sharp turn remarkably affect the local heat transfer distributions [27]. The flow visualization tests also revealed that secondary flows were generated in the turn region [28].…”