Rocket Propulsion Elements, 9th Edition

CHAPTER 14SOLID PROPELLANT COMBUSTION AND ITS STABILITY

In this the third of four chapters on solid propellant rocket motors we discuss combustion of solid propellants, physical and chemical processes of burning, ignition or start‐up process, extinction of burning, and combustion instability.

When compared to other power plants, the combustion process in rocket propulsion systems is very efficient because gas composition in solid propellant reactions is essentially uniform and combustion temperatures are relatively very high; these two accelerate the rate of chemical reaction, helping to achieve nearly complete combustion. As mentioned in Chapter 2, the energy released in combustion can be between 94 and 99.5% of the total available. This is difficult to improve, so rocket motor designers have been concerned not so much with the burning process as with controlling combustion (start, stop, and heating effects) and with preventing the occurrence of combustion instabilities.

14.1 PHYSICAL AND CHEMICAL PROCESSES

Combustion in solid propellant motors involves exceedingly complex reactions taking place in the solid, liquid, and gas phases of heterogeneous mixtures. Not only are the physical and chemical processes occurring during solid propellant combustion not fully understood, but analytical combustion models have remained oversimplified and unreliable. Experimental observations of burning propellants show complicated three‐dimensional microstructures and other flame structures, ...