Abstract
The effect of transverse pitch between a pair of delta-winglet vortex generators arranged in a common flow down configuration on the symmetrical flow structure and heat-transfer performance was numerically investigated. The results showed that symmetrical longitudinal vortices form a common flow down region between the vortices. The fluid is induced to flow from the top towards the bottom of the channel in the common flow region, which is advantageous to the heat transfer of the bottom fin. The vortex interaction increases and the vortex intensity decreases along with the decrease in transverse pitch of vortex generators. Vortex interaction has a slight influence on pressure penalty. The Nusselt number decreases with increasing vortex interaction. The vortices gradually attenuate and depart from each other during the process of flowing downward. A reasonable transverse pitch of delta-winglet vortex generators in a common-flow-down configuration is recommended for high thermal performance.
Highlights
Improvement of the heat-transfer efficiency can decrease the size, weight, and cost of heat exchangers
Reported that the Vortex generators (VGs) arranged on both fin surfaces of the flow channel can simultaneously increase heat transfer and decrease pressure loss compared with the plane VG under the same VG area
The results showed that an optimal arrangement of VGs exists for the best heat-transfer enhancement by considering the vortex interaction
Summary
Improvement of the heat-transfer efficiency can decrease the size, weight, and cost of heat exchangers. Reported that the VGs arranged on both fin surfaces of the flow channel can simultaneously increase heat transfer and decrease pressure loss compared with the plane VG under the same VG area. Lu and Zhai [22] numerically studied the performance of tear-drop VGs in common flow up They found that tear-drop VGs can enhance the heat transfer with a negligible increase in the pressure drop. The results showed that an optimal arrangement of VGs exists for the best heat-transfer enhancement by considering the vortex interaction. As the vortex interaction significantly affects the heat transfer, it is meaningful to study the vortex interaction to find the optimal transverse pitch of a pair of VGs for the highest thermal performance.
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