A general tool for LTE thermochemistry for adiabatic non-diffusive reactive fluid dynamics: Applications to 2D planar discontinuity flows in SPH

Chemical reactions in fluid dynamics deeply modify physical flow conditions through the contribution of the energy from reactions, as well as through the variations of the mean molecular weight and of the ratio of specific heats. This occurs typically on time scales largely much smaller than the diffusive time scales of chemicals, especially for shock waves due to explosive events. In this work we show how it is possible to include a stand alone algorithm, dealing with both molecular and nuclear thermochemistry in a computational unreactive, non-diffusive, adiabatic flow dynamics in local thermal equilibrium (LTE) within an explicit scheme of integration, free of the adopted computational framework. To this purpose, we worked using the Free Lagrangian GASPHER framework, belonging to the smooth particle hydrodynamics methods (SPH). Assuming the same initial physical conditions, some comparisons are made among reactive to unreactive 2D planar discontinuity flows, assuming the same initial chemical compositions as simple as possible for a better understanding of the role not only of the thermochemical reaction energy, but also of the mean molecular weight and of the ratio of specific heats in fluid dynamics.