Ignition and Structure of a Laminar Diffusion Flame in a Compressible Mixing Layer with Finite Rate Chemistry
Abstract
In this paper we consider the ignition and structure of a reacting compressible mixing layer using finite rate chemistry lying between two streams of reactants with different freestream speeds and temperatures. Numerical integration of the governing equations show that the structure of the reacting flow can be quite complicated depending on the magnitude of the Zeldovich number. In particular, for sufficiently large Zeldovich number, the three regimes first described by Linan and Crespo (1976); i.e., ignition, deflagration, and diffusion flame, occur in supersonic as well as in subsonic flows. An analysis of both the ignition and diffusion flame regimes is presented using a combination of large Zeldovich number asymptotics and numerics. This allows us to analyze the behavior of these regimes as a function of the parameters of the problem. For the ignition regime, a well defined ignition point will always exist provided the adiabatic flame temperature is greater than either freestream temperature. One important result is that at supersonic speeds ignition occurs far downstream from the plate and, as the flow is accelerated to hypersonic speeds, ignition is exponentially delayed. For the diffusion flame regime, the location of the flame changes significantly with changes in the equivalence ratio and the Schmidt numbers.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1991
- Accession Number
- ADA236525
Entities
People
- C. E . Grosch
- T. L. Jackson