To solve weakness of self-rotating driving force, deficiency on capacity of resisting high temperature of plastic twisted strip, as well as abrasion, a scheme, which settles the heat-resistant and abrasion-resistant problems by plastic coat and intensifies the capacity of transferring self-rotating driving force by installing driving wheel at the tube inlets, is proposed. Results indicate that such spiral insert can achieve auto-cleaning at low speed and can be widely utilized. In addition, its cleaning capacity is great. The enhancement of convective heat transfer is as great as 52.6%, which ...