Rate-Controlled Constrained-Equilibrium (RCCE) Modeling of Propulsive Performance of Energetic Materials in a Hypersonic Nozzle

摘要

The rate-controlled constrained-equilibrium (RCCE) method for simplifying the kinetics of complex reacting system is reviewed. This method is based on the maximum entropy principle of thermodynamics and involves the assumption that evolution of a system can be described using few set of slowly changing constraints imposed by external and internal dynamics of the system. As a result, the number of differential and algebraic equations required to determine the constrained-equilibrium state of a system can be very much smaller than the number of species. The method has been applied to the oxidation of methane in a constant volume adiabatic chamber. The results of using 12 constraints (12 differential equations) are in perfect agreement with detailed chemistry using 29 species. The model, then, was applied to the expansion of combustion products of methane during the power stroke of an internal combustion engine. Results of using 8 constraints were in an excellent agreement with those of detailed chemistry. Reacting gas mixture through a nozzle was analyzed using detailed chemistry, and properties such as temperature and pressure as a function of location were determined. The combined analysis of flow through nozzle and rate-controlled constrained- equilibrium model has been developed and calculations are being made now.