Investigate of Flow and Heat Transfer Characteristics of Longitudinal Vortex Generators Periodical Fitted in Narrow Rectangular Channel

Wang Ling ◽  
Huang Jun
2012 ◽  
Vol 455-456 ◽  
pp. 356-362
Chun Hua Min ◽  
Ya Ju Qin ◽  
Cheng Ying Qi

A novel combined longitudinal vortex generator, comprising a rectangular wing mounted with an accessory rectangular wing, was introduced and the turbulent flow and heat transfer characteristics of a rectangular channel with rectangular winglet pair and combined winglet pair were numerically analyzed. The effects of six parameters were examined. The results show that in the range of the present study, the increase of the six parameters can result in the increase of heat transfer and pressure drop. Specially, the pressure drop decrease at large value of the distance of accessory wing from the channel bottom. The effect of the main attack angle of the combined winglet pair is somewhat different to that of the rectangular winglet pair. The heating plate temperature of the channel with combined winglet pair is lower than that of the channel with rectangular winglet pair, and hence the heat transfer is enhanced.

2015 ◽  
Vol 138 (1) ◽  
Lu Zheng ◽  
Yonghui Xie ◽  
Di Zhang ◽  
Haoning Shi

Passive flow control and heat transfer enhancement technique has become an attractive method for device internal cooling with low resistance penalty. In the present paper, the flow and heat transfer characteristics in the small scale rectangular channel with different groove–protrusions are investigated numerically. Furthermore, the combination effect with ribs is studied. The numerical results show that on the groove side, the flow separation mainly occurs at the leading edge, and the reattachment mainly occurs at the trailing edge in accordance with the local Nusselt number distribution. On the protrusion side, the separation mainly occurs at the protrusion back porch and enhances the heat transfer at the leading edge of the downstream adjacent groove. The rectangle case provides the highest dimensionless heat transfer enhancement coefficient Nu/Nu0, dimensionless resistance coefficient f/f0, and thermal performance (TP) with the highest sensitivity of Re. When ribs are employed, the separation bubble sizes prominently decrease, especially inside the second and third grooves. The Nu/Nu0 values significantly increase when ribs are arranged, and the one-row case provides the highest heat transfer enhancement by ribs. Besides, the two-row case provides the highest Nu/Nu0 value without ribs, and the three-row case shows the lowest Nu/Nu0 value whether ribs are arranged or not.

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