Thermomechanical Concepts and Modeling for Stability Physics in Liquid-Propellant Rocket Engines

Thermomechanical concepts and modeling are used to describe the response of inert and reactive gases to transient, spatially resolved thermal energy deposition. The ultimate goal is to establish the cause–effect relationship between combustion-generated energy deposition and the mechanical disturbances responsible for operationally observed pressure oscillations in liquid-propellant rocket engine combustion chambers as well as to identify physical processes that convert thermal energy to kinetic energy. Asymptotic formulations of the nondimensional describing transient conservation equations for both inert and reactive gases are used to identify nondimensional parameters that characterize fundamental physics occurring as the gas responds to localized heating. The characteristics of the responses depend upon the magnitudes of the suite of parameters. Some are described by hyperbolic partial differential equations; others involve either nearly constant density or nearly isobaric phenomena. Thermomechanical ...