Analysis of acid vapor condensation characteristic and corrosion level of integrally-rolled spiral finned tube heat exchanger via CFD and ANN method

Integrally-rolled spiral finned tube (IRSFT) has superior thermal-hydraulic performance in waste heat recovery. However, low-temperature corrosion often leads to equipment failure, and the relevant anti-corrosion researches have not been reported. To guide the performance improvement, the acid condensation and corrosion characteristics of IRSFT heat exchangers are numerically investigated using CFD method coupled with acid vapor condensation and artificial neural network (ANN) models. The distribution characteristics show that the region of angle θ = 10° for the first row and θ = 60° for the other rows may suffer from severe corrosion due to the intense flow perturbation, and the critical number of tube rows 5 was determined with the decreasing temperature and vapor concentration. Meanwhile, the influence of working parameters was analyzed, and the primacy of wall temperature and water vapor content for corrosion regulation was confirmed owing to the significant contribution rate and practicality. Further, based on the performance criteria proposed by considering the synergistic effects on acid corrosion, the real corrosion level was evaluated using the predictive relationships of ANN and the full-factor results, and effective anti-corrosion safety zones were derived. Our finding can provide a valuable reference for the anti-corrosion performance enhancement of flue gas heat exchangers.