Chapter 4 - Combustion Chambers for Airbreathing Engines

Abstract

The attributes of good combustion chamber for airbreathing engines and appropriate modeling of the chemical energy release are described. The special cases of combustors with constant area and those with constant pressure are developed in detail using the quasi-one-dimensional equations developed in Chapter 2. The fuels used in airbreathing engines and their characteristics, such as fuel-air ratios, are derived. Then the concept of combustor efficiency is introduced and practical combustor configurations and methods for thermal management are discussed. The special case of supersonic combustion for high-speed vehicles is considered. The criteria for chemical equilibrium are developed and the means for calculating equilibrium chemical compositions using equilibrium constants is derived. Equilibrium chemistry calculations are illustrated and the concept of the adiabatic flame temperature is introduced. A technique for calculating the adiabatic flame temperature and an example appropriate to liquid propellant combustion completes the chapter.