高效传热强化斜齿扭带及其低流速自动清洗技术

现有流体动力塑料光滑扭带不能用于流速低于1.0 m•s^-1的传热设备的污垢自动清洗、传热强化幅度不高.为此研制了一种高效强化传热、又能够在1.0～0.5 m•s^-1的较低流速下自动清洗污垢的斜齿扭带.其原理是在光滑扭带的两面上等距离地排列斜齿，被斜齿导向的传热流体对斜齿的反作用力形成一个新增的旋转力矩.与现有的光滑扭带相比，弧线形斜齿扭带自转清洗力矩增大了75％～101％、传热系数提高了171％.虽然斜齿扭带的阻力系数较高，但是设备的总阻力仍然在一般工程容许的范围内，具有广阔的应用前景.

Twisted strip with oblique teeth to efficiently remove fouling and enhance heat transfer at low flowing velocity

The plastic smooth twisted tape can not be used for heat exchangers with low fluid velocity of less than 1.0 m•s^-1 to prevent and remove fouling and it can not enhance heat transfer.A new twisted strip was proposed to enhance heat transfer.It was capable of being used in the circumstances with lower flow velocity of 0.5 m•s^-1.Oblique teeth were attached asymmetrically on both surfaces of the twisted strip at regular intervals.The fluid for heat transfer was directed by the teeth with asymmetrical reaction forces on the twisted strip to form an additional rotating moment.With this arrangement,total moment was increased by 75%～101% and heat transfer coefficient was raised by 171% as against that of the smooth twisted strip.Though the resistance coefficient of fluid flow became greater, the total flow resistance of the equipment was still within the permissible range of engineering application, e.g. for a heat exchanger of 4 tube circuits and 6 meter long tubes, the resistance was about 36000 Pa.The new twisted strip could be used to automatically remove fouling and enhance heat transfer with low flow velocity of 0.5—1.0 m•s^-1.