WP1: EXPERIMENTS AND INITIAL CONDITIONS
1. The combination of selected non-intrusive techniques resulted in an improved vision of the cavitating flows which are used for validation of computational simulations.
2. Combination of the experiments with a modelling effort, enable a deeper analysis and understanding of the bubble and jet dynamics. Data will be valuable in the development of models for cavitation-bubble-induced spray break-up.
3. Offered a better description of the flow in the nozzle. The way the TAP has been analysed and the results this analysis returned are progresses in the field of liquid atomization mechanism.
4. The CFD methodologies developed in this project can bring new insights into the complex multiphase flow phenomenon, produce new physics understandings, generate innovation ideas. The tools can lead towards higher precision products that contribute to the reduction of CO2 and toxic emissions over engine lifetime.
WP2: DNS ON PRIMARY/SECONDARY ATOMISATION
1. The produced data can be used in the derivation of collapse-induced atomization models for problems of larger scales; while also valuable insight gained into the mechanisms that lead to the development of high levels of pressure within the flow and on nearby surfaces.
2. Droplet size statistics and droplet velocity distributions have been determined with unprecedented detail for conditions relevant for upper stage rocket engines and orbital manoeuvring systems using direct numerical simulations and high performance computing capabilities. These DNS data are to be used for LES model development and future LES will aid combustor development and lead to the replacement of the current toxic hypergolic fuels by environmentally more friendly alternatives based on cryogenic liquids.
3. Proposed accurate numerical methods that can be used in the Navier-Stokes equation solver for simulating the physical configurations of aero-engine fuel injection.
4. For the first time, simulations for the breakup of droplets were performed at representative engine conditions (Diesel, scramjet and marine) as well as for cluster formations (tandem, parallel and combined). Correlations and simultions produced can be utilized in macroscopic CFD codes for the simulation of sprays, which can be utilized to design an efficient fuel injection system with a potential reduction in NOx emissions
5. It was observed that, for a range of conditions, breakup of a W/HFO emulsion droplet is faster and more optimized relative to the aerodynamic breakup of the corresponding neat HFO droplet. That information could be utilized as modeling insights for the simulation of W/HFO emulsion sprays.
WP3: HOLISTIC LES MODEL DEVELOPMENT
1. With the help of comparison with experimental data was observed that ELSA formulation using LES has the potential to simulate realistic fuel injection systems; the same formulation can be used to simulate injection systems in aerospace sector.
2. The developed multiscale numerical method has been developed for realistic engineering applications and differentiates from the analytical solutions of theoretical purposes.
3. The develop models use novel probabilistic approaches to determine the evolution of the liquid volume and surface as the liquid breaks into droplets and fragments. The results show that the method not only provides good predictions in air-blast atomizers but can also be applied directly to other types of fuel injectors, such as Diesel sprays for internal combustion engines.
4. Contribution towards predictive LES by developing a physics based LES SGS model for turbulence modulation effects in sprays. The model is based on a stochastic modeling approach called one-dimensional turbulence (ODT) resolving all scales. The model allows predictions of turbulence modulation effects in parameter regimes relevant to engineering problems which are mostly beyond the capabilities of DNS.
5. The new hybrid Euler-Euler and Euler-Lagrange model i.e. VOF-to-DPM is validated with the collaboration of ANSYS GmbH. This modeling approach is currently used for the prediction of the spray for MHPSE oil burners. A detailed study is carried out to compare the different operational parameters; there effect on internal nozzle flow and subsequent atomization
