Development and validation of a direct passage arrangement method for multistream plate fin heat exchangers

Abstract

Passage arrangement quality significantly affects the performance of multistream plate fin heat exchanger (MPFHEs) because a bad arrangement may result in uneven temperature difference field and pressure field between passages and thus reduce the thermal efficiency. However, it is very difficult to design an effective passage arrangement owing to large numbers of possible passage arrangement patterns and complex heat transfer processes between the passages in a MPFHE. This work develops a direct passage arrangement method for MPFHEs to address this problem. In this method, an improvement of passage arrangement with good synergistic heat transfer effect is first proposed. The determination of passage quantity for each fluid is suggested to be proportional to its design heat load. Next, based on the results of the checking calculation, the fin and heat exchanger structure parameters should be adjusted until the constraints including thermal effectiveness, length deviation and pressure drops have been satisfied. Afterwards, the passages are arranged directly by a symmetry arrangement method. To evaluate the effectiveness of this method, three different industrial cases are performed and compared with the existing optimization designs by three evaluation means. The validation results indicate that this method performs better than the complex optimization methods.