Large-eddy Simulation of a Water Jet Exhausting into Quiescent Air
Abstract
Large quantities of water are injected in the motor jet plume to reduce the noise levels generated by rocket engines. This study focuses on the water injection system and more precisely on the destabilization of the liquid jet that leads to a spray system. For that purpose, a large-eddy simulation (LES) is conducted for an experimental water jet of the literature. It is a sprinkler whose Reynolds number is = 82, 000 and nozzle exit diameter is = 4.37 mm, corresponding to injectors used for jet noise reduction studies at a reduced scale. A diffuse interface method is used to calculate the dense liquid phase, and the dispersed phase containing droplets is calculated with an Eulerian solver. Transfers between the dense and the dispersed phases are modeled in the coupling procedure, including the atomization process. A synthetic-eddy method (SEM) is also applied in the water inlet region to force the jet transition. Different grid sizes are tested to evaluate the sensitivity of the results. The evolution of the mean jet radius along the axis is found to be in good agreement with the experimental data and the most unstable frequency obtained in the jet shear layer by the LES is similar to that observed in the experiment. Finally, a methodology based on the instability waves developing at the interface is used to estimate the diameter of atomized droplets. First qualitative results of the simulation with atomization are presented.
Domains
Engineering Sciences [physics]Origin | Files produced by the author(s) |
---|