Journal of Safety and Environment

To investigate the atomization and flow field characteristics of a traditional straight-blade half-inch centrifugal water mist nozzle and a newly designed structurally optimized airfoil-blade counterpart， a comprehensive series of experimental tests and numerical simulations was systematically conducted. The experimental phase utilized a custom-built closed-loop water circulation testing platform integrated with a high-precision Phase Doppler Particle Analyzer (PDPA)， enabling accurate， real-time measurement of various macroscopic and microscopic spray parameters. Specifically， fluid flow rate， spray angle， maximum average axial velocity， and droplet diameter distribution were evaluated under varying inlet pressure conditions ranging from 0.5 MPa to 4.0 MPa. Concurrently， to uncover internal flow mechanisms that are not easily observed in physical experiments， Computational Fluid Dynamics (CFD) simulations were performed using Fluent software. The numerical model incorporated the RNG k–ε turbulence model coupled with the Volume of Fluid (VOF) multiphase framework to capture complex air-water interface dynamics. We simulated internal static pressure variations， velocity distributions of the internal flow field， and outlet cross-sectional velocity profiles for both nozzle geometries under extended inlet pressures from 1.0 MPa to 6.0 MPa. The empirical data demonstrate that the optimized nozzle significantly enhances fluid throughput. Within the tested pressure range， its flow rate increased by 20% to 35% compared to the traditional design， peaking at a maximum flow difference of 1.039 m³/h under the 2.0 MPa working condition. Furthermore， the airfoil-blade structure exhibits a broader operational range for the spray angle， contracting from 78.8° to 46°， which provides a distinct spatial coverage advantage， particularly around the 1.5–2.0 MPa pressure interval. Interestingly， regarding droplet size distribution， a crossover effect was observed: the traditional straight-blade nozzle generates finer droplets at lower pressures (0.5–2.5 MPa)， while the optimized nozzle demonstrates superior atomization performance at higher pressures exceeding 3.0 MPa. Both designs successfully achieved effective droplet velocities surpassing 50 m/s once system pressure reached 3.5 MPa. From a numerical perspective， simulation results illustrate that structural optimization significantly smooths the internal pressure gradient; specifically， at the extreme pressure of 6.0 MPa， the local pressure drop across the blades is reduced by approximately 57%. This research provides a theoretical basis and data accumulation for the selection and structural optimization of water mist nozzles， serving as a valuable reference for dust protection in mining operations.