INFLUENCE OF SUSPENSION GENERATION ON DUST EXPLOSION PARAMETERS

摘要

Combustion mechanisms of a suspension of solid particles in a gaseous mixture are studied with the aim of correlating the constant volume explosion characteristics with the initial state of the suspension at ignition time. Two vessels have been specially designed, one transparent with an octagonal cross section, allowing visualization and, the other steel made, able to support 50 bar overpressure to measure combustion characteristics. Particle dispersion in the chamber is achieved by means of the turbulent flow created by the discharge of pressurized air. Experiments were made with cornstarch particle suspensions. Evolution of the flowfield and dust distribution were recorded with high-speed imaging, LDV and PIV. The required delay to obtain an optimal mixture is between 500 and 700 ms. For a stoi-chiometric cornstarch dust-air mixture, explosion characteristics are in satisfactory agreement with results obtained by other researchers. Theses values decrease with initial rms velocity.