The design of liquid-fueled engines requires an understanding of the injection and atomization phenomena occurring in the combustion chamber. Traditional methods for modeling such processes are based on the Navier-Stokes equations and require an accurate knowledge of the constituent transport and material properties and an accurate equation of state. This can be particularly difficult as one approaches the critical pressures and temperatures of the constituents.Molecular dynamics is used to simulate low Reynolds number liquid injection and jet breakup. The use of molecular dynamics allows the atomization to occur "naturally," without the need for tracking phase boundaries, and intrinsically includes all physical processes, material properties, and equations of state in both subcritical and supercritical environments. Three-dimensional molecular dynamics simulations of a laminar liquid nitrogen jet injected into subcritical gaseous nitrogen have been conducted. Simulations were conducted at pressures from atmospheric to just below critical (3.38 MPa) and liquid and gas temperatures from 76 to 124 K. Jet Reynolds numbers ranged from approximately 1 to 4, and the Weber numbers based on gas density ranged from approximately 0.04 to 7.0. For the low Reynolds and Weber number regime Rayleigh breakup is reproduced with the resulting drop sizes matching Rayleigh theory. In addition, the effect of ambient pressure on the simulated jet breakup length agrees well with general trends. Satellite drop formation was also observed. The first-ever simulations of the onset of the first wind-induced breakup regime can be seen in the cases of higher gas pressures and Weber numbers.
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)