In this paper, the implication of various grades of hydrogen rich gas on the in-cylinder flame speed, and on the knock propensity, are discussed. The laminar flame propagation speed of methane with various grades of hydrogen-rich gas addition has been calculated. The effect of adding hydrogen, hydrogen rich gas from an ideal reformer (synthesis gas), as well as that from a non-catalytic plasmat...

The propagation speed of a thin premixed flame disturbed by an unsteady fluid flow of a larger scale is considered. The flame may also have a general shape but the reaction zone is assumed to be thin compared to the flame thickness. Unlike in preceding publications, the presented asymptotic analysis is performed for a general, multi-step reaction mechanism and, at the same time, the flame front...

Microscopic turbulence-flame interactions of thermonuclear fusion flames occuring in Type Ia Supernovae were studied by means of incompressible direct numerical simulations with a highly simplified flame description. The flame is treated as a single diffusive scalar field with a nonlinear source term. It is characterized by its Prandtl number, Pr ≪ 1, and laminar flame speed, SL. We find that i...

The effects of H2 enrichment on the propagation of laminar CH4–air triple flames in axisymmetric coflowing jets are numerically investigated. A comprehensive, time-dependent computational model, which employs a detailed description of chemistry and transport, is used to simulate the transient ignition and flame propagation phenomena. Flames are ignited in a jet-mixing layer far downstream of th...

This work is dedicated to the analysis of the delicate details of the effect of upstream velocity fluctuations on the flame propagation speed. The investigation was carried out using the Sivashinsky model of cellularisation of hydrodynamically unstable flame fronts. We identified the perturbations of the steadily propagating flames which can be significantly amplified over finite periods of tim...

The laminar flame speed of Dimethyl Ether (DME)/air mixtures at room temperature and atmospheric pressure were determined experimentally over an extensive range of equivalence ratios, with and without 15% nitrogen dilution, using Particle Image Velocimetry (PIV) and a stagnation flame burner configuration. The laminar flame speeds were determined by linear extrapolation of the measured referenc...

The effect of O(3) on C(2)H(4)/synthetic-air flame propagation at sub-atmospheric pressure was investigated through detailed experiments and simulations. A Hencken burner provided an ideal platform to interrogate flame speed enhancement, producing a steady, laminar, nearly one-dimensional, minimally curved, weakly stretched, and nearly adiabatic flame that could be accurately compared with simu...

In this paper we study the behavior of a premixed turbulent methane flame in three dimensions using numerical simulation. The simulations are performed using an adaptive time-dependent low Mach number combustion algorithm based on a second-order projection formulation that conserves both species mass and total enthalpy. The species and enthalpy equations are treated using an operator-split appr...

This Note is concerned with the speed of propagation of a chemical reaction in a fast, steady and non uniform flow, which may apply to flame propagation in some instances. The structure of the flow is 1) a parallel shear flow with velocity perpendicular to the average front, where the flame speed is close to the maximum flow speed toward the fresh gases 2) a periodic cellular structure where th...

We investigate the propagation of a premixed flame subject to thermal expansion through a narrow channel against a Poiseuille flow of large amplitude. This is the first study to consider the effect of a large-amplitude flow, characterised by a Péclet number of order one, Pe= O(1), on a variable-density premixed flame in the asymptotic limit of a narrow channel. It is also the first study on Tay...