Using the inlet/outlet temperatures, calculate the Log Mean Temperature Difference. Use the correction factor charts (Chapter 17 of the PDF) for multiple passes.
Donald Q. Kern’s Process Heat Transfer (1950) remains one of the most cited textbooks in chemical engineering, primarily due to its systematic, stepwise method for designing shell-and-tube heat exchangers. This paper critically reviews the Kern method, presenting its fundamental assumptions, key equations for film coefficients and pressure drop, and a worked example. We compare the Kern approach with modern computational fluid dynamics (CFD) and the more rigorous Bell-Delaware method. While the Kern method introduces significant simplifications (e.g., ideal tube row assumption, constant bypass/leakage), it retains pedagogical and industrial value for preliminary design and troubleshooting. We conclude that the Kern method is not obsolete but rather serves as an essential conceptual bridge to advanced thermal design. dq kern process heat transfer pdf