Optimization to the tube–fin contact status of the tube expansion process

The tube–fin contact status is an important factor influencing both thermal resistance and service life of the tube–fin heat exchanger. Tube expansion process brings forming defects of gaps at the tube–fin interfaces. And elimination of this forming defect is proved to be difficult. This paper presents a novel method in improving the tube–fin contact status of heat exchanger. From simulation results, distribution of the contact pressure along the tube–fin interface can be obtained. Then, an optimization process integrated with FE simulation is established for the sectional profile of the fin collar. The fin collar is represented with spline curves. Results show that after the optimization, the gap at the tube–fin interfaces is basically eliminated and the tube–fin contact status is significantly improved. Furthermore, flanging process for the optimized sectional shape of the fin collar is discussed.