To Study on Ignition Characteristics of Syngas Mixtures by Shock Tube 2013-01-0118
Ignition delay of undiluted syngas mixtures with different compositions of H₂, CO, CO₂, N₂ and air was measured using a shock tube. Experiments were conducted under various conditions of pressure of 0.2 and 1.0 MPa, temperature from 757 to 1280 K, and equivalence ratio of 0.3 and 1.0. The testing data set was analyzed based on methods including: Arrhenius-type correlation (to assess the effect of pressure, temperature, equivalence ratio, and fuel composition on ignition characteristics), use Davis's mechanism (to calculate ignition delay). The obtained results using Arrhenius-type correlation and Davis's mechanism showed a far difference from experimental values. A detailed analysis was conducted to evaluate the influence of perturbation from shock tube experiments on chemical induction time of the syngas. The ignition delays, considered the effect of non-ideal conditions, are shorter than ones which predicted with ideal conditions. Measured pressure curves were also used to further simulate, the achieved ignition delays have approached to experimental values. Additionally, the most important reactions in combustion process were pointed out and discussed through sensitivity analyses. The research results may contribute to improvement of the current chemical kinetics and mechanisms and be applicable in research and development of equipments operating with syngas fuels.