The flow and heat transfer characteristic in outward convex corrugated tube combined with insert twisted tube (CT) was numerically studied based on the three-dimension RNG k-ε model. A comparison is proposed between the numerical results and experimental results in order to check the reliability of numerical model. Comparative study on flow and heat transfer between the CT and conventional smooth tube (ST) is performed in order to review the compound heat transfer enhancement mechanism. The results show that compared with ST

the heat transfer performance and overall heat transfer performance of CT increase by 1.48 and 1.3 respectively

and more obvious in the low Reynolds number. Detached vortex is formed between the corrugatoion and twisted tape in CT

breaking the thermal boundary layer. Disturbance is increased by twisted tape in the main flow region

meanwhile

turbulence kinetic energy increase. Therefore

compound heat transfer enhancement is achieved by synergistic effect between the corrugation and twisted tape.