Kinetic modeling of detonation and effects of negative temperature coefficient

TL;DR

This paper develops a new kinetic hydrodynamic model using non-equilibrium quantities to simulate and analyze detonation phenomena, including the negative temperature coefficient regime, revealing differences in hydrodynamics and entropy production.

Contribution

A novel hydrodynamic model replacing viscous stress and heat flux with NOMF and NOEF, enabling detailed simulation of detonation behaviors including NTC effects.

Findings

Good agreement of viscous stress and NOMF near equilibrium

Deviations of NOMF and NOEF at sharp interfaces

Differences in entropy production among detonation types

Abstract

The kinetic modeling and simulation of reactive flows, especially for those with detonation, are further investigated. From the theoretical side, a new set of hydrodynamic equations are deduced, where the viscous stress tensor and heat flux are replaced by two non-equilibrium quantities that have been defined in our previous work. The two non-equilibrium quantities are referred to as NonOrganized Momentum Flux (NOMF) and Non-Organized Energy Flux (NOEF), respectively, here. The numerical results of viscous stress (heat flux) have a good agreement with those of NOMF (NOEF) near equilibrium state. Around sharp interfaces, the values of NOMF (NOEF) deviate reasonably from those of viscous stress (heat flux). Based on this hydrodynamic model, the relations between the two non-equilibrium quantities and entropy productions are established. Based on the discrete Boltzmann model, four kinds of detonation phenomena with different reaction rates, including Negative Temperature Coefficient (NTC) regime, are simulated and investigated. The differences of the four kinds of detonations are studied from three aspects: hydrodynamic quantities, non-equilibrium quantities and entropy productions.