Finite element analysis of bending forming of fin tube heat exchanger

Heat exchanger bending is a key forming technique applied in mass production for air conditioning industry. In order to improve the production efficiency, multilayer bending technique is used more widely. However, compared to the traditional single-layer bending process, contact stress between fins and bending die of multilayer bending forming process is much larger. The risk of crush of fins is increased and therefore thermo performance of heat exchanger is reduced. In this paper, the multilayer bending process of fin-tube heat exchanger is studied by using the finite element method. 3D model of the forming process is established based on the wave shape fin and experiment is carried out to validate the simulation result. The comparison results indicate the agreement between FEM and experimental results. The formability parameters, such as normal pressure, von mises stress and plastic strain are numerically studied. The reason and prediction method of fin crushed are discussed, which are helpful in processing parameters setting and mold design.