Direct Numerical Simulations of Turbulent Combustion- Temperature Inhomogeneity Effects on the Autoignition of H2/Air Mixtures in the Sponteneous Ignition Regime
EMSL Project ID
8219
Abstract
Recent DNS of lean hydrogen-air ignition at high pressure at constant volume with temperature inhomogeneities showed the dual significance of scalar dissipation- first, limiting the minimum attainable ignition front speed, and second, modulating the initial spectrum of temperature gradients, thereby promoting spontaneous front propagation rather than deflagration. We will investigate this latter effect in greater detail by simulating over a wider range of turbulence and initial temperature distributions than before. We anticipate that larger initial integral length scales of the temperature field that are more representative of HCCI combustion, will favor the spontaneous ignition front mode of propagation. The data from these simulations will be used to develop closure approximations in models of the reaction rate in the spontaneous ignition regime.The runs will carry detailed H2/air chemistry for low-temperature autoignition kinetics (Mueller et al.) and will have 4 million grid points to resolve all of the scales. The runs require 600,000 timesteps to proceed through ignition and consumption of all of the reactants in the domain. This represents a physical timescale of approximately 3 milliseconds.
Project Details
Project type
Exploratory Research
Start Date
2004-04-06
End Date
2005-12-15
Status
Closed
Released Data Link
Team
Principal Investigator