| A computational code is developed to determine the high-temperature and high-pressure combustion products of energetic materials inside a closed, constant-volume, adiabatic vessel assuming chemical equilibrium occurs. The product mixture is modelled as a mixture of gases with pure condensates dispersed uniformly. To solve this problem, the Villars-Cruise-Smith (VCS) minimization algorithm is applied. This algorithm is based on a stoichiometric formulation using chemical equations and is optimized to avoid matrix inversions during iterations. Procedures are also implemented for treating trace gaseous species and the special situation of phase transitions of condensed substances. The resulting Extended-VCS (E-VCS) code is flexible, robust and easy to use. Different models and complicated equations of state can be used for describing the mixture of gases and the products, and systems with several hundred species can be handled. The solution algorithm and procedures of the E VCS code are compared with those of three previous major codes for the same analysis, the Bagheera, Blake and NASA-Lewis codes, using a range of test problems. The E-VCS code straightforwardly solves problems with many condensed products, including near gasless conditions and phase transitions—problems the previous major codes have difficulty solving. |
