Abstract: In order to further study the two-phase flow device with the best combination of flow field and parameters inside the mixing chamber, six two-phase flow atomizing nozzles with different structures were designed in this paper. The relevant atomization characteristic parameters such as droplet size, droplet axial velocity, atomization angle and fog flux were experimentally determined. Based on the experiment, the velocity flow field, pressure flow field and gas-liquid volume fraction inside the mixing chamber were simulated by Fluent software, so as to supplement and verify the experimental results. The optimal working parameters of the nozzle are as follows: liquid working pressure is 0.4 MPa, liquid mass flow is 60.0 kg/h, gas working pressure is 0.6 MPa, gas mass flow is 0.1 kg/h, nozzle diameter is 0.8 mm and injection number is 32.

Key words: bubble atomizing, numerical simulation, nozzle structure, fire extinguishing effect