Effective Techniques for Augmenting Heat Transfer: An Application of Entropy Generation Minimization Principles

摘要

The techniques for heat transfer augmentation play an important role in the development of efficient and inexpensive equipment for heat exchange processes. In the present study, the effectiveness of a given augmentation technique was determined based on the amount of irreversibility (waste of useful energy) introduced by the technique into the heat exchanger where it is to be used. This report summarizes the main results obtained during the past two years under research contract N00014-79-C-0006 at the University of Colorado. The report is organized into three distinct parts. The first part contains a fundamental investigation of the entropy generation mechanism in elementary heat transfer configurations. The second part describes in quantitative terms the irreversibility minimization potential of some of the most common augmentation techniques, namely, swirl-flow devices and roughened surfaces. The final part considers the entropy generation penalty associated with the use of extended surfaces (fins) in convective heat transfer. This part shows how the fin geometry may be selected so that the fin performs its prescribed heat transfer duty with minimum generation of entropy. (Author)