缩放管内带衰减性自旋流的复合强化传热研究

Compound heat transfer enhancement in converging-diverging tube with delaying self-sustaining swirl flow

以水、质量分数50%和85%的甘油为工质,对缩放管内分别插入的10种不同结构形式旋流片的传热性能进行实验研究。结果表明:相同实验流量范围内,以传热强化综合因子η为目标,在水为介质下,η均小于1,不适用。在质量分数50%甘油为工质下,旋流片的扭率为2.52,旋转角为180°,间距为383 mm时,η最大,在1.08—1.12;在质量分数85%甘油为工质下,旋流片的扭率为2.02,间距为288 mm,旋转角为180°时,η最大,在1.17—1.22。

The heat transfer of converging-diverging tubes with 10 different twisted-tapes inserted respectively was experimentally studied with water,mass fraction 50% and 85% glycerin as working fluid respectively.Taking the valuation factor of heat transfer as target,the results indicate that heat transfer η is less than 1 under the condition of water medium,which means it doesn′t enhance at all;however,the max η is 1.08-1.12 with the twisted rate 2.52,twist angle 180°and spacing 383 mm under the condition of mass fraction 50% glycerin medium and the max η is 1.17-1.22 with twisted rate 2.02,spacing 288 mm and twist angle 180° under the condition of mass fraction 85% glycerin medium.