This paper proposes a design for a corrugated fin-tube heat exchanger, where a pair of ellipsoidal protrusions are stamped out at the rear of each tube. The ellipsoidal protrusions have similar functions to traditional flat or curved vortex generators, which can generate longitudinal vortices in the flow channel. It was found that corrugated fin-tube heat exchanger has region with low heat transfer ability, and ellipsoidal protrusions will be set in this region to intensify heat transfer. An small region is chosen as computational domain. The ellipsoidal protrusions with heights ranging from 2.1 to 2.4 mm is used. The RNG k-ε turbulence model and the finite volume method are used to study the turbulent flow and heat transfer characteristics in the channel. The numerical results show that the combination of ellipsoidal protrusions and corrugated fins can effectively enhance the intensity of secondary flow and improve heat transfer. Compared with the smooth channel of corrugated fins, the averaged Nusselt number of the ellipsoidal protrusions is increased by 8.53%, and both Nu and f increased with the increase in the height of the ellipsoidal protrusions. When the heat performance factor reached the maximum value of 1.154, the height of the ellipsoidal protrusions was 2.4 mm.
 

heat exchanger; corrugated fin; ellipsoidal protrusion; heat transfer enhancement