Page 6 - Bird R.B. Transport phenomena

Preface

While momentum, heat, and mass transfer developed independently as branches of
classical physics long ago, their unified study has found its place as one of the funda-
mental engineering sciences. This development, in turn, less than half a century old, con-
tinues to grow and to find applications in new fields such as biotechnology,
microelectronics, nanotechnology, and polymer science.
Evolution of transport phenomena has been so rapid and extensive that complete
coverage is not possible. While we have included many representative examples, our
main emphasis has, of necessity, been on the fundamental aspects of this field. More-
over, we have found in discussions with colleagues that transport phenomena is taught
in a variety of ways and at several different levels. Enough material has been included
for two courses, one introductory and one advanced. The elementary course, in turn, can
be divided into one course on momentum transfer, and another on heat and mass trans-
fer, thus providing more opportunity to demonstrate the utility of this material in practi-
cal applications. Designation of some sections as optional (o) and other as advanced (•)
may be helpful to students and instructors.
Long regarded as a rather mathematical subject, transport phenomena is most impor-
tant for its physical significance. The essence of this subject is the careful and compact
statement of the conservation principles, along with the flux expressions, with emphasis
on the similarities and differences among the three transport processes considered. Often,
specialization to the boundary conditions and the physical properties in a specific prob-
lem can provide useful insight with minimal effort. Nevertheless, the language of trans-
port phenomena is mathematics, and in this textbook we have assumed familiarity with
ordinary differential equations and elementary vector analysis. We introduce the use of
partial differential equations with sufficient explanation that the interested student can
master the material presented. Numerical techniques are deferred, in spite of their obvi-
ous importance, in order to concentrate on fundamental understanding.
Citations to the published literature are emphasized throughout, both to place trans-
port phenomena in its proper historical context and to lead the reader into further exten-
sions of fundamentals and to applications. We have been particularly anxious to
introduce the pioneers to whom we owe so much, and from whom we can still draw
useful inspiration. These were human beings not so different from ourselves, and per-
haps some of our readers will be inspired to make similar contributions.
Obviously both the needs of our readers and the tools available to them have
changed greatly since the first edition was written over forty years ago. We have made a
serious effort to bring our text up to date, within the limits of space and our abilities, and
we have tried to anticipate further developments. Major changes from the first edition
include:
• transport properties of two-phase systems
• use of "combined fluxes" to set up shell balances and equations of change
• angular momentum conservation and its consequences
• complete derivation of the mechanical energy balance
• expanded treatment of boundary-layer theory
• Taylor dispersion
• improved discussions of turbulent transport

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