缩放管内间隔插入旋流片的复合强化传热

提出一种复合强化传热方法，对四种不同间隔插入旋流片的缩放管进行了传热与流阻实验研究,并与普通光滑圆管、缩放管空管、内插旋流片的光滑圆管三种结构条件进行比较.通过综合评价,在实验范围内(3400

Compound Heat Transfer Enhancement of A Converging-diverging Tube Inserted with Spaced Twisted-tapes

A compound heat transfer enhancement mechanism is presented. Pressure drop and heat transfer characteristics by a combination of a converging-diverging tube with regularly spaced twisted-tape elements in four different spaces have been investigated experimentally. For comparison, experiments in a smooth circular tube and a converging-diverging tube without twisted-tape were carried out. The evaluation results show that in the range of Reynolds number 3400-20000, when the twisted-tapes with 68 mm in length and 180° in rotation angle are inserted with 700 mm in space in the converging-diverging tube, the valuation factor of heat transfer increases 21%、15% and 16％ over that in the cases of smooth circular tube, converging-diverging tube without twisted-tapes and smooth circular tube with spaced twisted-tapes, respectively. It is seen that the compound enhanced tube, converging-diverging tube inserted with regularly spaced twisted-tape elements, has a good performance on doubled enhancement of heat transfer.