Combustion Characteristics of Natural Gas/Air Flat Premixed Laminar Flames in a Developed Matrix Burner

Abstract

The natural gas flat flame characteristics are experimentally and numerically investigated under different equivalence ratios. A matrix burner is designed so that the natural gas-air mixture from the matrix burner makes up the flat flame. The combustion characteristics, such as the flame lift, the flame thickness, the gas temperatures, and the species concentration, are measured. The measured species concentrations are compared to the computed concentrations using different chemical kinetic mechanisms. The work was carried out at atmospheric pressure and room temperature at different equivalence ratios of 0.6, 0.8, 1, 1.2, and 1.4. A close agreement occurs between the experimental and the simulation results at lean and stoichiometric conditions with a mean absolute error value ranging from 0.9:3. At stoichiometric conditions, the maximum measured gas temperature, the flame thickness, and the minimum flame lift-off all coincide with the maximum simulated mole fractions of CO2 and NO. In addition, the centreline axial temperature is low just above the burner top (i.e., the flame lift region). However, those temperatures increase as the distance above the burner top increases.