Hydrophobic nano SiO2 as flow-enhancing additives and flame retardant synergizes with CaCO3 to suppress gas explosion

The suppression effect of hydrophobic nano SiO2 of different concentrations as flow-enhancing additives synergizing with CaCO3 to inhibit gas explosions was systematically studied in a self-built LabVIEW-based explosion test platform. The results showed that the addition of hydrophobic powder can reduce the angle of rest and enhance the flowability of mixed powders, and improve the powder diffusion effect and storability. Meanwhile, changing the proportion and concentration of the mixed powders had a significant impact on the combustion reaction, so that the flame propagation velocity and explosion overpressure decreased significantly. However, excessive powder concentration will promote the combustion reaction at the initial stage of the explosion, and the synergistic inhibition effect of the two powders on explosions is better than that of a single powder. Based on the above results, the optimum suppression concentration and proportion were determined, the mechanism of suppressing gas explosion by a powder was analyzed, and the coupling relationship between flame velocity and pressure was summarized.