高温高压液氨喷雾宏微观特性试验与仿真

The spray characteristics of liquid ammonia under high-temperature (690~1100K) and high-pressure (1. 0—4. 0 MPa) conditions were systematically investigated by combining experiment and numerical Simulation, aiming to develop an accurate prediction model for liquid ammonia spray. The experimental analysis employed high-speed shadow-graphy to capture the dynamic spray process, while the numerical Simulation based on the Lagrangian-Eulerian coupling approach, focused on key parameters such as velocity fields, Sauter mean diameter(SMD), and probability density function (PDF). The results reveal that increasing ambient pressure weakens the axial spread of the spray while enhancing radial expansion, reducing spray penetration, lowering tip velocity, and increasing the cone angle (with a maximum increase of 86. 13%). Higher ambient temperatures significantly promote evaporation and diffusion effects but have limited impact on spray penetration and cone angle. The experiment shows that at 690 K and 1.0 MPa, ammonia undergoes flash boiling, causing significant spray expansion and an increased cone angle. Furthermore, the spray velocity field and droplet distribution exhibit high sensitivity to pressure variations, with SMD decreasing significantly (maximum reduction of 42.83%) and PDF shifting toward smaller droplets, thereby improving atomization Performance. The reliability of the developed model for predicting liquid ammonia spray behavior was validated.