HEAT TRANSFER HANDBOOK Adrian Bejan

HEAT TRANSFER

HANDBOOK

Adrian Bejan

Heat transfer has emerged as a central discipline in contemporary engineering science. The research activity of a few decades ago—the material reviewed in the first handbooks—has distilled itself into textbook concepts and results. Heat transfer has become not only a self-standing discipline in the current literature and engineering curricula, but also an indispensable discipline at the interface with other pivotal and older disciplines. For example, fluid mechanics today is capable of describing the
transport of heat and other contaminants because of the great progress made in modern convective heat transfer. Thermodynamics today is able to teach modeling, simulation, and optimization of “realistic” energy systems because of the great progress made in heat transfer. Ducts, extended surfaces, heat exchangers, and other features that may be contemplated by the practitioner are now documented in the heat transfer literature.
To bring this body of results to the fingertips of the reader is one of the objectives of this new handbook. The more important objective, however, is to inform the reader on what has been happening in the field more recently. In brief, heat transfer marches forward through new ideas, applications, and emerging technologies. The vigor of heat transfer has always come from its usefulness. For example, the challenges of energy self-sufficiency and aerospace travel, which moved the field in the 1970s, are still with us; in fact, they are making a strong comeback. Another example is the miniaturization revolution, which continues unabated. The small-scale channels of the 1980s do not look so small anymore. Even before “small scale” became the fashion, we in heat transfer had “compact” heat exchangers. The direction for the future is clear.
The importance of optimizing the architecture of a flow system to make it fit into a finite volume with purpose has always been recognized in heat transfer. It has been and continues to be the driving force. Space comes at a premium. Better and better shapes of extended surfaces are evolving into networks, bushes, and trees of fins. The many surfaces designed for heat transfer augmentation are accomplishing the same thing: They are increasing the heat transfer rate density, the size of the heat transfer enterprise that is packed into a given volume.
The smallest features are becoming smaller, but this is only half of the story. The other is the march toward greater complexity. More and more small-scale features must be connected and assembled into a device whose specified size is always macroscopic. Small-scale technologies demand the optimization of increasingly complex heat-flow architectures.

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