  Chemical reactions in fluid dynamics deeply modify the flow physical
conditions through both the contribution of the energy of reactions and the
variation of the mean molecular weight and of the ratio of specific heats. This
occurs typically on time scales largely much smaller than diffusive time scales
of the produced chemicals, especially for shock waves coming from explosive
events. In this work we show how it is possible to include a standing alone
algorithm, dealing with both molecular and nuclear thermochemistry in the
computational nondiffusive adiabatic flow dynamics in local thermal equilibrium
(LTE) in an explicit scheme of integration of fluid dynamics equations, free of
the adopted computational framework. In this paper, working in the Free
Lagrangian GASPHER framework, belonging to the smooth particle hydrodynamics
methods (SPH), some comparisons are made for planar discontinuity flows among
reactive to the respective unreactive flow models, assuming the same initial
physical conditions and simple chemical composition. Results show the
importance of the role not only of the thermochemical reaction energy, but also
of the mean molecular weight and of the ratio of specific heats.
