天然气层流燃烧特性的实验与数值计算

The flame propagation characteristics and laminar combustion speeds of natural gas (0.9 methane/0.07 ethane/0.03 propane, mole fraction) were experimentally tested in the constant volume bomb under the conditions of the pressures of 0.1, 0.2, 0.3 MPa, the equivalence ratios range of 0.7− 1.4, the temperatures of 300, 350, 400 K, the contents of O₂ of 15%, 18%, 21%, the contents of CO₂ and H₂O of 0%, 10%, 20%. Meanwhile, the simplified reaction mechanism of natural gas (including 40 species and 189 reactions) was constructed by sensitivity analysis and other methods, and the laminar combustion speeds of natural gas were calculated numerically. The results showed that as the equivalent ratio increased from 0.7 to 1.4, the laminar combustion speeds of natural gas rose and then declined, and the peak appears near the equivalent ratio was 1.1; With the increase of initial temperature and the content of O₂ or the decrease of initial pressure, the contents of CO₂ and H₂O, the laminar combustion speeds gradually increased. The simplified reaction mechanism of natural gas constructed hereto can better predict the overall trends of the laminar combustion speed with the equivalent ratio. However, the predicted values were slightly lower than the experimental values under certain conditions.