Numerical investigation of injection variation in the bidirectional vortex

The primary goal of this work is to assess the sensitivity of the bidirectional vortex to changes in injection conditions. To achieve this goal, a parametric model is developed to capture the effect of variations in injector quantity, size, velocity, and location. The resulting cold-flow model is simulated using OpenFOAM, anopen-source platform for the solution of fluid dynamics problems. The accuracy of the solver is validated through comparisons to existing analytical models. After validation, velocity and pressure profiles are examined to assess the response of the vortex structure to changes in the injector design. It is found that increasing mass flow rate by way of injector number, injector size, and injection velocity all have an amplifying effect on the peak velocity magnification. Changes in the injection height have a negligible effect on the swirl velocity and pressure but a more significant impact on the axial velocity. Finally, the vortex Reynolds number and the swirl number are identified as dimensionless parameters that control the vortex structure.