Enhanced heat transfer technology is an energy-saving technology. For new types of tube inserts

the mechanism of the rotors-assembled device for heat transfer enhancement and automatic cleaning is introduced in this paper. Experiments were carried out in order to study the heat transfer and friction characteristics of the tube inserted with helical blade rotors and discrete blade rotors. An experiment with a smooth tube was used to calibrate the experimental system and data reduction method. The experimental results show that the Nusselt number from the tube inserted with rotors is higher than that of plain tube within the experimental range of Reynolds number

though the friction factor of the tube with rotors inserted is slightly higher. The comparison of the tubes inserted with helical blade rotors and discrete blade rotors shows that the former present higher Nusselt number

lower friction factor and higher PEC value

indicating that the comprehensive performance of helical blade rotor is better.