Numerical simulation of time-dependent reacting flows in pulse facilities Original Research Article

A numerical methodology for simulating time-dependent reacting flows inside several types of pulse facilities is outlined in this paper. The numerical approach uses a finite-volume Harten–Yee TVD scheme for the quasi-one-dimensional Euler equations coupled with finite rate chemistry. To track gas interfaces a Riemann solver is included and to reduce the number of nodes without smearing the interfaces, a moving mesh is used. The source terms representing the finite-rate chemical kinetics and vibrational relaxation are often large and make the algorithm too stiff to be advanced explicitly. To avoid this stiffness an implicit treatment of these source terms is implemented. The numerical program can work with 13 chemical reacting species and 33 different reactions of a hydrogen–oxygen–nitrogen combustion mechanism, each of which may proceed forward or backward. Since helium is often used in pulse facilities it is also included, although it is considered as an inert species. Numerical simulations showing the potential of the computer code for the prediction of fluid mechanic properties and the chemical composition of the flow inside pulse facilities, are presented.