U bend finned tube is widely used in power, chemical industry and other industries. Many spiral heat exchange surface or threaded tube can be regarded as U bend finned tube. It has a significant effect on the expansion of heat transfer area and the promotion of turbulence, both for single-phase convective heat transfer and phase-change convective heat transfer. The structure of U bend finned tube heat exchanger is basically the same as that of shell and tube heat exchanger. Only U bend finned tube is used instead of smooth tube as heat transfer surface. U bend finned tube heat exchanger is often used to heat or cool the gas outside the tube, and the tube is filled with steam or water, such as air cooler, boiler economizer, radiator, etc.