ABSTRACT
Perhaps the most significant advances in enhanced heat transfer technology have been made in special surface geometries that promote high-performance nucleate boiling. These special surface geometries provide an increased heat transfer coefficient. Although the surface area may be increased, it is common to define the boiling coefficient in terms of the projected, or flat plate, surface area. That “roughness” can improve nucleate boiling performance has been known for 60 years, but for nearly 35 years this was regarded as an interesting, but commercially unusable concept because the heat transfer improvement lasted for only a matter of hours before “aging” caused the performance to decay to the plain surface value. In the period 1955 to 1965, fundamental advances were made in understanding the character of nucleation sites and the shape necessary to form stable vapor traps. This understanding provided a basis for industrial research (1960 – 1975) that led to the development of commercially viable enhanced surface geometries. The first of these high-performance geometries was patented in 1968. By 1980, six nucleate boiling surface geometries were commercially available.
