Heat transfer performance comparisons of five different rectangular channels with parallel angled ribs

Numerical study on overall thermal performance in SAH duct with compound roughness of V-shaped ribs and dimples

“…The boundary conditions for the V-shaped ribs combined with dimple ribs are applied as experimental conditions. [7][8][9][10][11][12][13][14][15][16][17][18] Fi g. It is therefore, RNG k-ε model has been employed for the present CFD study. Fig.4 shows the velocity profiles for the V-down shaped ribs combined with dimple ribs with different values of α = 35°-70°, and kept other rib parameters used to roughened an air duct with a fixed value of Re=8000.…”

“…5,6) Han et al 7) experimentally investigated the effects of rib shape, angle of attack and pitch-to-rib height ratio on friction factor and heat transfer coefficient. Park et al 8) presented the results of heat transfer and friction factor data measured in five short rectangular channels with turbulence promoters. Lau et al 9) carried out experiments to study the turbulent heat transfer and friction for fully developed flow of air in a square channel with discrete rib turbulators.…”

“…Saini and Verma 23) reported the experimental results of the turbulent fluid flow and heat transfer characteristics in a rectangular air channel with a dimpled roughness shape attached to the underside of a heated plate. They changed the range of Reynolds number from 2000 to 12000 with the relative roughness heights of 0.018-0.037 and the relative roughness pitches of [8][9][10][11][12]. For the range of parameters investigated, Nusselt number was found to be the maximum corresponding to relative roughness height of 0.0379 and relative roughness pitch of 10.…”

Effect of Alterations in V-down Rib on the Performance of an Artificially Roughened Solar Air Heater Duct

“…Initial studies (Han et al, 1978;Gupta et al, 1993) used ribs positioned at 90° to the direction of flow for periodic interruption of the primary flow and reported enhancement in the heat transfer with considerable pressure drops. With the aim to further enhancing the rate of heat removal with lesser pressure drop penalty, studies were performed using inclined ribs (Han and Park, 1988;Park et al, 1992) and good amount of improvement in the performance was observed as compared to the transverse ribs. Flow visualization studies through a duct roughened with inclined ribs (Taslim et al, 1996) revealed that, flow moving along the ribs (secondary flow) after striking the end wall of the duct, takes the shape of a recirculation vortex.…”

“…In an effort to further enhance the heat transfer in ribbed channels, discrete ribs in various configurations were tested and it was observed that broken ribs performed better than their continuous counterparts in all cases (transverse, inclined, V-shaped) with comparatively smaller pressure loss penalties (Park et al, 1992;Fann et al, 1994;Gupta et al, 1997;Momin et al, 2002;Mulluwork, 2000). These studies reported that, airflow over a staggered array of angled discrete ribs separates not only at the top edges of the ribs but also at the ends of the ribs.…”