Basic Instability Mechanisms in Chemically Reacting Subsonic and Supersonic Flows
Abstract
The structure, sustenance and stability of gaseous detonations are believed to be the result of complex interactions between chemical kinetics and gas dynamics. Recent studies on two-dimensional detonations further show the initiation and the sustenance of a transverse wave structure through such interactions. In channels of large widths (in terms of characteristic reaction lengths), transverse waves develop rapidly in initially planar detonations undergoing longitudinal oscillations. For very narrow channels, however, only longitudinal waves are observed, because waves of short wave lengths or high frequencies are attenuated. Analysis of the observed low-frequency instability in dump combustors shows that the oscillations are triggered and sustained by interactions between non-uniform entropy zones and pressure waves. Rarefaction waves incident on the flame zone cause the flame to stretch and separate, forming a zone of low entropy. The non-uniform entropy zones then generate compression and rarefaction waves, as they are convected with the flow through the choked nozzle. Development of instability in a shear flow was examined. Exothermic reaction tends to augment the growth rate of the accompanying Tollmien-Schlichting waves. (edc)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1981
- Accession Number
- ADA215023
Entities
People
- G. E. Abouself
- T. Y. Toong
Organizations
- Massachusetts Institute of Technology