A general tool for LTE thermochemistry for adiabatic nondiffusive fluid dynamics: applications to 2D planar discontinuity flows in SPH

TL;DR

This paper introduces a versatile algorithm for incorporating LTE thermochemistry into adiabatic nondiffusive fluid dynamics within SPH, enabling detailed analysis of reactive flow phenomena such as shock waves.

Contribution

It presents a standalone thermochemistry module compatible with SPH that accurately models chemical and nuclear reactions in adiabatic flows without relying on specific computational frameworks.

Findings

Reactions significantly influence flow conditions through energy and molecular weight changes.

Thermochemical effects alter the dynamics of planar discontinuity flows.

The model highlights the importance of reaction energy, molecular weight, and specific heats in flow behavior.

Abstract

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.