SIMULATION OF AMMONIA SPRAY UNDER BOTH NORMAL EVAPORATING AND SUPERHEATED CONDITIONS

Abstract

A predictive three-dimensional Eulerian-Lagrangian framework for ammonia spray is suggested, and its evolution characteristics under both normal evaporating and superheated conditions are unraveled. First, a simplified boundary model considering the effects of superheated fluid behaviors within the nozzle on the injection velocity and angle was proposed. The real vapor-liquid equilibrium theory is applied in the evaporation model to improve the prediction accuracy of the phase change. An explosion model with the homogenous nucleation theory was used to simulate the burst process. Then, the spray experiment for the liquid ammonia under varied conditions was conducted, and the high-speed diffused back illumination and schlieren approaches were adopted to measure the spray evolutions. Following that, the simulation results were verified against the experimental data under both normal evaporating and superheated conditions, and good agreements indicated that the suggested framework was feasible to accurately and efficiently simulate the evolutions and morphology of ammonia spray. Finally, the transient evolution characteristics of ammonia spray under various conditions were discussed. The heavy cooling effect of ammonia evaporation makes the initial fuel temperature have a notable effect on its spray penetration and expansion.