1. The books by Williams,1Williams-Barrere-Huang,2and Price-Culick3are strongly recommended to readers as excellent introductions and References texts in the areas respectively of general combustion, solid-propellant rocket motors, and solid-propellant burning. Technology and research on solid-propellant burning have been developed in USSR along very autonomous and successful lines for the last 40 years. This is basically due to the pioneering and 666 L. DE LUCA extraordinarily advanced work performed by Ya.B. Zeldovich during World War II. Fortunately, two monographs are available containing detailed discussions of Soviet progress. The first,by Novozhilov,4was published in Moscow in 1973 and the secondly Zeldovich-Leypunskiy-Librovich,5was published in Moscow in 1975 but is based on a short course given by Librovich6in 1970 during a stay at Princeton University. Finally, a collection of specialized articles on experimental techniques in solid-propellant combustion was recently published.7This book also should be of great interest to readers.
2. It is not always obvious to distinguish between static and dynamic extinction. This is not a mere academic exercise, for different physical mechanisms and different boundaries apply. Unfortunately, great confusion exists on this point in the competent literature. While the static extinction boundary has been recognized since the beginning as a property of the propel 1ant, the dynamic extinction boundary is usually considered to depend on the transition parameters (e.g., initial and final pressure, depressurization rate, experimental apparatus, type of forcing function, etc.). The author8showed in 1975 that the dynamic extinction boundary also is a property of the propel 1ant, fixed by the actual set of operating conditions, but independent of initial values, experimental apparatus, type of forcing function, etc. For example, a parabolic deradiation in time to zero flux intensity at 10 atm and an exponential depressurization from 30 to 10 atm without radiation assistance feature the same dynamic extinction limit (for a given propellant). A first detailed report of this theory and some numerical verifications were included in the Ph.D. thesis of the author.9An up-to-date exposure of the theory, with further extensions, is given in Ref. 10. This also includes a wide range of numerical verifications and some preliminary experimental checks.
3. Among the very numerous contributions (see, e.g., Refs. 11-47) to fast depressurization extinction, the only paper which clearly recognized the difference between static and dynamic extinction limits was offered by T'ien20in 1974. However, a totally different approach was followed and not all the conclusions in this excellent paper are shared by the writer. Details will be given later.
4. Fast deradiation extinction, being a recent discovery, has drawn much less attention (see, e.g., Refs. 48-53). The intimate connection between dynamic extinction by fast depressurization and fast deradiation was not recognized by anyone before Ref. 8 appeared.