Weak Detonations Revisited: Uncovering Its General Nature Using Autoignitive Reaction Wave Concept

TL;DR

This paper demonstrates that stable weak detonations can be naturally achieved through supersonic autoignitive reaction waves, providing a universal framework that simplifies realization conditions and broadens potential applications.

Contribution

It introduces autoignitive reaction waves as a new, stable mechanism for weak detonations, establishing their equivalence with Rayleigh flow and providing universal realization criteria.

Findings

Autoignitive reaction waves are mathematically equivalent to Rayleigh flow.

Stable weak detonations occur when inlet velocity exceeds Chapman-Jouguet velocity.

The framework applies to any reactive system without specialized chemistry.

Abstract

Weak detonations have remained experimentally elusive since their theoretical prediction, with previous realization attempts requiring either pathological detonations or Zeldovich spontaneous waves. Here, we demonstrate that stable weak detonations are naturally achieved through supersonic autoignitive reaction waves a recently proposed concept describing inherently stable reaction waves determined by inflow velocity conditions and autoignition characteristics. We establish the mathematical equivalence between autoignitive reaction waves and classical Rayleigh flow, proving that supersonic autoignitive reaction waves are indeed weak detonations. The underlying thermodynamic structure reveals Legendre conjugate variables linking normalized enthalpy and fuel consumption. Unlike previous approaches, our universal realization conditions require only that inlet velocity exceed the Chapman-Jouguet velocity and autoignition criteria be met applicable to any reactive system without specialized chemistry. This framework transforms weak detonations from theoretical curiosities to practically achievable phenomena, opening new possibilities for applications in supersonic combustion systems and astrophysical phenomena.