Systematic comparative analysis of Kern and Bell-Delaware methods for the design of shell-and-tube heat exchangers

This study systematically compares the two most widely adopted manual calculation methods for predicting the performance of shell-and-tube heat exchangers: the Kern method and the more accurate, though more complex, Bell-Delaware method. The comparison is carried out across a broad set of cases, considering both identical shell-side geometries and optimized configurations that, for a given tube bundle geometry, minimize the pressure drop while achieving the same target shell-side heat transfer coefficient. The discrepancies between the two methods are analysed in relation to the different empirical correlations they employ. This approach allows for the identification of general trends, the evaluation of how design parameters influence the results, and the extraction of practical insights for researchers and designers. One key finding is that, when possible, increasing the number of sealing strips, rather than the number of baffles, to reach a desired heat transfer coefficient is more effective in minimizing pressure drop. Furthermore, both the ratio of heat transfer coefficients and the ratio of pressure drops predicted by the Bell-Delaware and Kern methods can vary significantly from unity, and both tend to increase monotonically with the normalized baffle spacing.