Keywords: heat exchangers, fouling, performance evaluation, entropy generation, exergy transfer, comparative study, first law, second law, thermodynamics, thermal resistance, heat transfer
Comparative study of the effect of fouling on heat exchangers performance based on the first and second laws of thermodynamics
An extensive investigation of the effect of fouling on heat exchangers performance has been carried out based on the first and second laws of thermodynamics. Non-dimensional fouling thermal resistance is firstly defined, and five typical criteria in terms of heat transfer units number, heat transfer effectiveness, exergy transfer units number, exergy transfer effectiveness and non-dimensional entropy generation number are considered. The corresponding expressions of variation rate before and after fouling are derived and numerically examined. It is found that these performance evaluation criteria can demonstrate the effect of fouling on heat exchangers performance in different ways. However, some of these performance evaluation criteria have limitations owing to their specific characteristics. This study provides valuable information regarding the design and operation of heat exchangers subjected to fouling condition.