缩放平行板间插入旋流片的复合强化传热

为了研究新型换热器--矩形管束换热器的传热性能,通过在缩放平行板间插入一组旋流片来研究旋流片下游的传热与流阻,并与光滑平行板、无旋流片缩放平行板的传热效果进行比较.实验结果表明:在实验范围内(19000

Compound Heat Transfer Enhancement by Parallel Converged-Diverged Plate Inserted with Twisted Tapes

In order to analyze the heat transfer performance of a new type of heat exchanger, namely, the rectangular tube-bundle heat exchanger, the characteristics of heat transfer and flow resistance of two parallel converged-diverged plates inserted with twisted tapes were experimentally investigated, and the results were then compared with those of smooth plates as well as with those of the parallel converged-diverged plates without twisted tapes. It is found that, when the Reynolds number varies from 19000 to 44000, both the local Nusselt number and the friction factor decrease with the increase of the distance from the tape tail, while the efficiency index of heat transfer enhancement first increases and then decreases;and that, when the Reynolds number is 19071 and the distance from the tape tail is 140mm, the efficiency index reaches the maximum, which is 15% and 9% higher respectively than that of the smooth plates and that of the parallel converged-diverged plates without twisted tapes. It is thus concluded that the parallel converged-diverged plates inserted with twisted tapes greatly enhance the heat transfer.