Nonsteady state combustion

If the pressure in a rocket motor changes during the time interval x, the pressure transient is considered to be steady state combustion when x > xc, and is nonsteady state combustion when x < xc. 

A monograph of Shchelkin Troshin (Ref 11) is based on studies at the Institute of Chemical Physics, Academy of Science, Moscow during the period 1952-1962, of theoretical analyses of detonation, deflagration, flame acceleration, nonsteady-state double discontinuities, and high-frequency oscillations in forced-combustion chambers. The book has been translated into English (See Ref 11a)... 

Despite intensive theoretical and experimental research on the combustion wave over the past decade, a universally accepted concept of the phenomenon has not been achieved. This is particularly true with respect to the nonsteady state phenomena of limits of inflammability and ignition. 

Frequently in theoretical work on the subject, whether dealing with the steady or nonsteady state, the mathematical development of an adopted model is followed by a descriptive summary of the results which is rarely traced back clearly to the assumptions inherent in the model. This has often resulted in extravagant identification of the model with the actual phenomenon and has been an obstacle in the task of reconciling conflicting views. There is need, therefore, of a purely descriptive exposition, stripped as completely as possible of mathematical language, to clarify the physical concepts of the combustion wave phenomenon. 

The first mechanistic KDIE correlation of the thermal decomposition process with explosive sensitivity was accomplished with the thermally initiated nonsteady—state thermal explosion event. The HMX thermal explosion event has been discussed and represents an intermediate temperature/pressure regime between the less drastic combustion event and the high order steady—state detonation event. Mechanistic KDIE detonation investigations recently have been conducted and provide the first correlation between the thermochemical decomposition process and shock—induced detonation using an exploding foil driven flyer plate test. i ... 

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