Transient reaction process and mechanism of cornstarch/air and CH4/cornstarch/air in a closed container: Quantitative research based on experiments and simulations

Both dust/air explosion and flammable gas/dust/air explosion are common forms of energy release. Experiments and simulation models with a multi-step chemical reaction mechanism were used to study the intensity parameters and mechanism of the CH4/air explosion, cornstarch/air explosion and CH4/cornstarch/air explosion in a closed container. Results showed that the peak overpressure, maximum flame temperature, and average flame propagation speed of the stoichiometric CH4/air explosion reach 0.84 MPa, 2614 K and 3.5 m/s, respectively. The optimal concentration of cornstarch explosion is 750 g/m(3), and its peak overpressure, maximum flame temperature and average flame propagation speed are 0.76 MPa, 2098 K and 1.77 m/s, respectively. For a three-components system, adding methane can significantly increase the explosive intensity and combustion performance of cornstarch. The explosive intensity parameters (peak overpressure, maximum flame temperature, average flame propagation speed) of a certain concentration of cornstarch first increase and then decrease with the increase of methane concentration. The maximum explosion intensity parameters of a three-components system with a certain concentration of lean-methane/air are higher than that of single-phase, but always lower than that of the stoichiometric methane/air. Moreover, the mutual coordination of dust and combustible gas in energy release and the mutual competition mechanism in oxygen consumption are described.

Automated summary

The study shows that the explosion intensity parameters vary significantly under different conditions, with CH4/air explosion exhibiting higher intensity than cornstarch/air explosion. Adding methane can enhance the explosive intensity of cornstarch, but this effect decreases after a certain concentration is reached.