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In an effort to capture the complex evolving interface of internal and external flow in an effervescent atomizer, a compressible Eulerian method, along with the volume-of-fluid method coupled with the large eddy simulation model, are employed in a two-phase flow system. Water is injected into the atomizer with a constant mass flow rate of 0.0133 kg/s (i.e., 800 mL/min). The mass flow rate of air is adjusted to vary the gas-to-liquid ratio (GLR) from 0.55% to 2.6%. It is observed that the increase in the GLR is accompanied by an evolution of the internal flow from a complex bubbly flow to an annular flow, which consequently reduces the liquid film thickness at the discharge orifice. Further studies on the internal pressure illustrate the critical condition, which leads to choked flow and pressure oscillations at the discharge orifice. Increasing the GLR was found to affect the internal flow, resulting in changes to primary atomization parameters such as a shortening of the breakup length and a widening of the spray cone angle. The numerical predictions are in good agreement with the experimental results under the same operating conditions.

In this study, a 3D two-way coupled Eulerian-Lagrangian approach is used to model the plasma jet and droplet-particle trajectory, velocity, and temperature achievable by suspension plasma spraying. A Reynolds stress model is used to account for turbulence and the effect of the substrate on the flow field and a Kelvin-Helmholtz Rayleigh-Taylor breakup model is used to predict the secondary breakup of the suspension. The focus of this work is on particle behavior near the substrate. Flat substrates placed at stand-off distances ranging from 40 to 60 mm are modeled to provide detailed information on particle impact behavior.