CFD Analysis on the Thermal Hydraulic Performance of an SAH Duct with Multi V-Shape Roughened Ribs

Abstract

This study presents the heat transfer and fluid flow characteristics in a rib-roughened SAH (solar air heater) channel. The artificial roughness of the rectangular channel was in the form of a thin circular wire in discrete multi V-pattern rib geometries. The effect of this geometry on heat transfer, fluid flow, and performance augmentation was investigated using the CFD (computational fluid dynamics). The roughness parameters were a relative discrete distance of 0.69, a relative rib height of 0.043, a relative rib pitch of 10, a relative rib width of 6.0, and a flow-attack-angle of 60˝. The discrete width ratios and Reynolds numbers ranged from 0.5 to 2.0 and from 2000 to 20,000, respectively. The CFD results using the renormalization k-epsilon model were in good agreement with the empirical relationship. This model was used to investigate the heat transfer and fluid flow characteristics in the multi V-pattern rib roughened SAH channel. The thermo-hydraulic performance was found to be the best for the discrete width ratio of 1.0. A discrete multi V-pattern rib combined with dimple staggered ribs also had better overall thermal performance compared to other rib shapes.

Aerodynamics and Heat Transfer over Solid-Deflectors in Transverse, Staggered, Corrugated-Upstream and Corrugated-Downstream Patterns

“…The third and final part of the paper then addresses the effects of rotation on heat transfer augmentation technologies for internal cooling. Kumar and Kim [6] presented the heat transfer and fluid flow characteristics in a rib-roughened solar air heater channel. The artificial roughness of the rectangular channel was in the form of a thin circular wire in discrete multi V-pattern rib geometries.…”

CFD Analysis on the Heat Transfer and Fluid Flow of Solar Air Heater having Transverse Triangular Block at the Bottom of Air Duct

“…However, our study focused on the effect of transvers triangular block installed at the bottom of air duct on the heat-transfer performance and fluid-flow characteristics. In many related previous studies, the uniform heat flux was applied as a boundary condition to investigate the heat-transfer performance and fluid-flow characteristics of solar air heaters [2][3][4][5][6][8][9][10]19,25,[28][29][30]. Thus, in this work, the uniform heat flux was chosen as a boundary condition to simulate solar energy.…”

“…Thus, the thermohydraulic performance parameter (THPP) was suggested by Webb and Eckert [32], as it evaluates the overall performance of the solar air heater, including both heat-transfer enhancement and increase in the friction factor. This parameter has been widely used to evaluate the performance of solar air heaters in the previous studies [3][4][5]10,[28][29][30] and is defined as follows:…”

“…Singh et al [9] investigated the heat and fluid-flow characteristics in a rectangular duct roughened with periodic discrete V-down rip. Kumar and Kim conducted a CFD-based analysis to investigate heat transfer and friction characteristics in rectangular channel with discrete multi-V-pattern ribs [10].The other method to improve the performance of a solar air heater is modifying the absorber plate. Karim and Hawlader [11] examined the performance of three types of solar air collectors having a flat-plate, v-corrugated, and finned absorber.…”

“…Singh et al [9] investigated the heat and fluid-flow characteristics in a rectangular duct roughened with periodic discrete V-down rip. Kumar and Kim conducted a CFD-based analysis to investigate heat transfer and friction characteristics in rectangular channel with discrete multi-V-pattern ribs [10].…”