A numerical investigation of reactive flow fields and species distribution in sonoreactors

• A Novel Numerical Simulation of Reactive Flow Fields have been conducted. • Water vapor decomposition during ultrasonic cavitation has been simulated. • Species distribution within the reaction zone is determined by flow patterns, reaction rates, and the availability of other species. In this paper, direct solution of the Navier-Stokes equation has been conducted to simulate the complex chemical reactions during the cavitation in the sonoreactors (ultrasonic reactors). In addition, a dynamic lattice vibrational boundary condition was used to simulate the reactive flow field in the evaporative cavitation region (water vapor decomposition). The finite-rate approach as well as an 11-step chemical mechanism were applied to solve the equations. The mixture approach along with the cavitation model of Singhal et al. were used to simulate the two-phase flow and k-ε RNG model was employed for the turbulence flow. The mean square error (MSE) between the simulation predictions and the experimental data was 0.0247, indicating a good agreement. Therefore, the simulation can be a valuable tool to study the chemical reactions in sonoreactors. The study of the effects of amplitude at five levels of 40, 60, 80, 100, and 120 μm (sound power) and species distribution in the sonoreactor reactive flow field revealed that the reaction zones remained below the horn tip at all amplitudes. Higher amplitudes generated larger bubbles, increased evaporative cavitation, and accelerated vapor species production and decomposition. The results showed that for a 20 kHz ultrasonic horn, evaporation cavitation occurs at the amplitudes higher than 60 μm. Altering the amplitude also changed the flow pattern, significantly impacting species distribution in the reaction zone.