Thilo F. Dauch

Smoothed Particle Hydrodynamics Simulation of Oil-Jet Gear Interaction

In this paper the complex two-phase flow during oil-jet impingement on a rotating spur gear is investigated using the meshless Smoothed Particle Hydrodynamics (SPH) method. A comparison of single-phase SPH to multi-phase SPH simulation and the application of the Volume of Fluid method on the basis of a two-dimensional setup is drawn. The results of the different approaches are compared regarding the predicted flow phenomenology and computational effort. It is shown that the application of single-phase SPH is justified and that this approach is superior in computational time, enabling faster simulations. In a next step, a three-dimensional single-phase SPH setup is exploited to predict the flow phenomena during the impingement of an oil-jet on a spur gear for various jet inclination angles. Thereby, a significant effect of the inclination angle on the oil spreading and splashing process is revealed. Finally, a qualitative comparison to an experimental high-speed image shows good accordance.

Computational Prediction of Primary Breakup in Fuel Spray Nozzles for Aero-Engine Combustors

This work was performed on the computational resource ForHLR Phase II funded by the Ministry of Science, Research and Arts Baden-Wurttemberg and DFG (”Deutsche Forschungsgemeinschaft“). In addition the authors would like to thank Rolls-Royce Deutschland Ltd & Co KG for the outstanding cooperation. The authors also are grateful for many lively and fruitful discussions with Simon Holz.

Modeling of the Deformation Dynamics of Single and Twin Fluid Droplets Exposed to Aerodynamic Loads

Droplet deformation and breakup plays a significant role in liquid fuel atomization processes. The droplet behavior needs to be understood in detail, in order to derive simplified models for predicting the different processes in combustion chambers. Therefore, the behavior of single droplets at low aerodynamic loads was investigated using the Lagrangian, mesh-free Smoothed Particle Hydrodynamics (SPH) method. The simulations to be presented in this paper are focused on the deformation dynamics of pure liquid droplets and fuel droplets with water added to the inside of the droplet. The simulations have been run at two different relative velocities. As SPH is relatively new to Computational Fluid Dynamics (CFD), the pure liquid droplet simulations are used to verify the SPH code by empirical correlations available in literature. Furthermore, an enhanced characteristic deformation time is proposed, leading to a good description of the temporal initial deformation behavior for all investigated test cases. In the further course, the deformation behavior of two fluid droplets are compared to the corresponding single fluid droplet simulations. The results show an influence of the added water on the deformation history. However, it is found that, the droplet behavior can be characterized by the pure fuel Weber number.