Effect of lateral fin profiles on stress performance of internally finned tubes in a high temperature heat exchanger

The thermal stress of the internally finned bayonet tube used for high temperature heat exchangers is numerically investigated by ANSYS software. Three kinds of lateral fin profiles, namely Z-shape, S-shape and V-shape are studied and compared. The significant temperature gradient and largest Von Mises stress are acquired. The largest stress is still generated in the joint of inner fin and outer tube due to the discontinuous change of the structure. The inner fin and inner tube are proposed to not be welded together to meet the reliability. The Z-shape has the best performance in both heat transfer and reliability, and is recommended for engineering application in high temperature heat exchangers.