Study of Finite-Rate Chemistry Effects on Turbulent Jet Diffusion Flames and Non-homogeneous Autoigntion Using the One-Dimensional Turbulence Model

Abstract

In current study Numerical simulation of turbulent combustion process is approached using One Dimensional Turbulence (ODT) model. The ODT model is based on the coupling of molecular processes (reaction and diffusion) with turbulent transport in a spatially- and temporally-resolved fashion over a one-dimensional domain. The domain corresponds to a transverse (or radial) direction; while, the transient evolution of the thermo-chemical scalars on the 1D domain represents the spatial evolution downstream of the jet inlet. The linear-eddy approach for modeling molecular mixing in turbulent flow involves stochastic simulation on a 1D domain with sufficient resolution to predict all relevant physical length scales properly. Firstly ODT is carried out to predict the hydrogen and air jet diffusion flame with helium dilution in the fuel. The comparison with existing experimental data was made for the numerical result of ODT simulation of jet diffusion flames in both conditional means and rms of scalars of measurements and computational results.

Another application of ODT was made in present work to verify the capability of prediction of autoignition (self-ignition) of one of free shear layer flow — jet diffusion flow. Different range of pressure and Reynolds number are set to identify the effects of turbulence intensity and mixture properties on the self-ignition chemistry. Autoignition delay time was studied based on these different conditions. At the same time the ability of the prediction of mixture temperature and species mass fraction profile were tested. A principle numerical result is expected and discussed. Conditional pdf and progress variable were used to analyze the computational result of ODT. Analysis was focus on the temperature growth and the mass fraction distribution of intermediate species and product.