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| Numerical Study of Vorticity Evolution in Spray Under Supercritical Condition |
| DOI：10.13949/j.cnki.nrjgc.2022.03.010 |
| Key Words:supercritical jet diffusion vorticity evolution large eddy simulation |
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| Abstract:Taking the n-dodecane spray test of Sandia National Laboratory as the research object， based on the open source software platform OpenFoam， the large eddy simulation method was used to simulate the spray process of n-dodecane in supercritical and subcritical environments. The Peng–Robinson equation of state and calculation methods of thermophysical properties and transport coefficients of real fluid were used. The spray penetration distance and fuel mass fraction were compared with experiment results to prove that spray model can accurately capture spray characteristics. Through the comparison of the spray process， the differences of the fuel diffusion and mixing process and the evolution process of the vortex in different conditions were researched. The results show that jet diffusivity and the diffusion angle under supercritical condition are both greater than subcritical condition， and diffusion and mixing efficiency of fuel in the supercritical environment is higher. In supercritical state， the jet will accelerate the formation of vortex and promote mixing of jet with surrounding gas. The velocity gradient is the main factor that determines evolution of vortex in high-speed jet. The existence of a large density gradient under supercritical condition will increase baroclinic torque， thereby promoting the development of vortex. Density gradient has an important influence on jet mixing. |
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