There are a wide variety of thermoacoustic phenomena. They are classified
as thermally induced spontaneous oscillations, prime movers, refrigerators, and
others. Recent progress in pulse-tube refrigeration is remarkable in Asia.
Common features of these phenomena are oscillation of fluid bounded by solid
matter and axial gradient of temperature. The traditional viewpoint of the
regenerator cannot describe functions of the stack and the pulse tube because it
neglects the irreversible process. Linear network analysis neglects effects of
the axial gradient of temperature. The thermoacoustic theory developed by N.
Rott includes both the irreversible process and the temperature gradient, and it
was supported by experiments on the stability limit of the spontaneous
oscillation. To understand the thermodynamic aspects of the theory, concepts of
heat flow and work flow were introduced. Interchange between these flows are
related to the axial gradient of temperature. Extension of the thermoacoustic
theory to include the progressive wave in addition to the standing wave made it
possible to understand devices equipped with the regenerator by the help of a
ASA 132nd meeting - Hawaii, December 1996