Study on the mechanism of surfactant droplet wetting and coagulation of respiratory dust: The case of AEO-9

[Display omitted] •The dynamic collision behavior of droplets with respirable dust is studied at the mesoscopic level based on CFD method with 6DOF dynamic grid.•The dust reduction by spraying with the addition of surfactant is investigated by fine level simulation and macroscopic experiment.•At a concentration of 0.14 % AEO-9, surface tension of 22.06 mN·m−1, static contact angle of 21.89°, the best wetting effect and droplet utilization rate were achieved when the droplet-to-dust particle size ratio was 2 ∼ 3 and V0 = 20 m/s ∼ 30 m/s liquid film was completely spread.•When a 1.2 mm diameter fine atomization nozzle is used, the highest percentage of droplets in the optimal interval is achieved at a spray pressure of 6 MPa.•Study on the mechanism of surfactant droplet wetting and coagulation of respiratory dust: the case of AEO-9. In industrial production, spraying is the most widely used dust control method. However, the traditional pure water spray has poor dust removal effect, and the principles of droplet wetting and dust encapsulation are unclear, resulting in poor dust removal effect. In this study, based on the CLSVOF method, we investigated the dynamic wetting and coalescence process of surfactant droplets and dust particles from a microscopic perspective. By changing the size ratio between the droplets and dust particles, as well as the initial velocity of the droplets, we simulated the spreading and wetting of surfactant droplets on the dust surface and found the optimal parameter range for encapsulating respirable dust. Through the experimental determination of spray atomization characteristics, it was found that the spray pressure of 6 MPa and the use of a 1.2 mm fine atomization nozzle produced a spray field with droplet sizes ranging from 14 to 21 μm, accounting for approximately 62.4 % of the distribution. Around 60 % of the droplets had velocities between 20 and 30 m/s. Dust settling efficiency experiments were conducted under these optimal spray parameters, and the settling efficiency of respirable dust reached 84.33 % within the favorable parameter range. Numerical simulations of the dynamic wetting process of dust-fog coupling at the microscopic level, as well as macroscopic spray experiments, were carried out to validate the reliable results. This method has significant implications for the control of respirable dust.