Study on Heat Transfer and Fouling Characteristics of 3D Micro-finned Tube Heat Exchanger With Extra-large Expanded Surface

The dust content in flue gas is an important reason that restricts the recovery efficiency of waste heat from flue gas. In this paper, heat transfer and fouling characteristics of a 3D micro-finned tube (3DMFT) heat exchanger are studied. Firstly, the heat transfer characteristics of circular tube and 3DMFT are compared. Then, the fouling characteristics of 3DMFT are explored, and the effect of gas velocity and particle diameter on fouling is revealed. The results show that, compared with circular tube, the heat transfer area of 3DMFT can be increased by 2.9 times; the heat transfer performance can be increased by 16% on average; the asymptotic fouling resistance can be reduced by 70%; meanwhile, the cleaning time is longer, which means the operation economy is better. To sum up, compared with traditional circular tube, the 3DMFT can enhance heat transfer, and also effectively reduce fouling. Therefore, it can be used as an efficient and anti-fouling heat transfer element in waste heat recovery systems.