TABLE OF CONTENTS The Delaware method for calculating the shell-side heat-transfer coefficient and pressure drop derives its name from a large industry sponsored study of shell-and-tube heat exchangers conducted at the University of Delaware, the final report of which was published in 1963 [1]. The method is often referred to as the Bell Delaware method, after one of the principal investigators on the project, Kenneth J. Bell.
The Delaware method utilizes empirical correlations for the heat-transfer coefficient and friction factor in flow perpendicular to banks of tubes; these are referred to as ideal tube bank correlations. In baffled heat exchangers, this type of flow is approximated in the regions between the baffle tips. In the baffle windows, however, the flow is partly parallel to the tubes. Furthermore, only part of the shell-side fluid follows the main flow path through the exchanger due to the presence of leakage and bypass streams in the shell. These deviations from ideal tube bank conditions are accounted for by a set of empirical correction factors for heat transfer and pressure drop. The correction factors for leakage and bypass flows are correlated in terms of the flow areas for the leakage, bypass, and main cross-flow streams.
Slightly different versions of the Delaware method have been published in various handbooks and textbooks, e.g., [2 6]. The presentation in this chapter is based on the version given by Taborek [2]. Consideration is restricted to exchangers with standard type E shells, single-cut segmental baffles, and un-finned tubes. The extension of the method...
