椭圆齿旋流口平带传热管内自动清洗及其传热强化

介绍了一种特殊结构的旋流口椭圆齿平带的研制。平带上的每个椭圆齿都是使平带自转的流体动力结构元素,平带两侧的旋流口结构能够使管内的部分液体形成螺旋线流,因而具有近似斜齿纽带那样能够在较低流速下自转实现管内污垢在线自动清洗的宝贵性能。由于椭圆齿后的大量涡流、管内部分液体流线转变为螺旋线流股以及螺旋线流股与轴向流股分合交错这样3方面的作用,管内的对流传热强化的幅度由此远远高于光滑纽带。试验结果表明,这种平带不仅容易制造,并且综合性能好,在管内流速0.5m/s左右就可运行;管内侧的传热系数提高170%,流体阻力在一般工程许可的范围内,因此具有较高的工程应用价值。

Automatic Fouling Removal and Heat Transfer Enhancement in Tubes Using Straight Strip-inserts with Elliptical Teeth and Broken Edge

This paper researches and develops the straight strip-insert of special structure, which has elliptical teeth and broken edge on both sides. The teeth are the elements to drive the insert self-rotate under the action of fluidic power. With the broken edge, part of the fluid in tubes is led to flow spirally. So, this straight strip with elliptical teeth can remove the fouling on tubes wall automatically at low flowing velocity just like that twisted strip with oblique teeth. The convection heat transfer enhancement is much more than that of the plain twisted strip because of three factors: much eddy flow behind the elliptical teeth, fluid flow being changed into spiral flow, and the combination and separation of the spiral flow and axial flow. The experiments show that this new insert can be manufactured easily and has great comprehensive performance. It can work reliably at a low velocity of 0.5 m/s and make the heat transfer coefficient inside tubes be increased by 170%. The flowing resistance is in the range of industrial permission. Therefore, it has great significance of industrial application