疏水涂层对内螺纹强化管表面污垢生长的影响

Compared with the plain tube, the fouling potential of the internally helical enhanced tube with higher heat transfer performance is also greatly improved. By coating the heat transfer surface with hydrophobic coatings, the interaction between pollutants and the surface can be reduced, thus inhibiting the fouling growth. Generally, the poor thermal conductivity of coating materials is not considered in the existing research. In this paper, the thermal and hydraulic characteristics of three coated enhanced tubes under clean condition are tested. It is found that the pressure drop of the system generally increases after surface modification, and the total heat transfer coefficient of the tubes decreases by 25%∼44%. Considering that the coating is a special "fouling", the thermal resistance of the coating is obtained by analogy with the calculation method of fouling thermal resistance. Referring to actual engineering conditions, the 1000 hours of accelerated combined fouling experiment was carried out at 0.9 m•s^-1. The results show that the induction period of the coating enhanced tubes with low surface free energy is significantly prolonged, but the effects of fouling inhibition are different. Among them, the comprehensive thermal resistance of coating B enhanced tube after fouling is still less than that of uncoated enhanced tube, which has practical application value.