Numerical investigations on the effect of convex-dimple streamwise arrangements on the flow and heat transfer characteristics of rectangular convex-dimple-grooved channels
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In this article, the effects of convex dimple streamwise arrangements on the flow and heat transfer characteristics of protrusion-grooved channels are determined, and five streamwise positions of convex dimples are considered. In addition, research on the transverse-circular-protrusion-grooved channel is also performed to serve as a contrast. The results indicate that replacing the transverse-circular-protrusion with the convex dimple produces a counter-rotating vortex pair, and the streamwise arrangements of the convex dimple significantly affect the flow structure downstream of the convex dimples. As the convex dimple is moved downstream, the velocities near the center protrusion-grooved surface increase till a maximum occurs for the case of a convex dimple placed at the center between adjacent grooves, and then decrease. Compared with the case of transverse-circular-protrusion, the convex dimple at the center region can enhance the overall heat transfer rate, while if it approaches the adjacent grooves lower heat transfer rate appears. Besides, replacing the transverse-circular-protrusion with the convex dimple can significantly reduce the pressure loss penalty and enhance the thermal performance factor. In addition, the effect of streamwise arrangements of convex dimples on the friction factor is slight, but the case with the center convex dimple exhibits the best overall thermal performance.
|Enheter & grupper|
Ämnesklassifikation (UKÄ) – OBLIGATORISK
|Tidskrift||Numerical Heat Transfer; Part A: Applications|
|Status||E-pub ahead of print - 2020 aug 11|
|Peer review utförd||Ja|