The goal of achieving low emission combustion in both stationary gas turbines and aero-engines requires a homogeneous fuel-air mixture. In liquid kerosene powered aero-engines engines, the particular challenge lies in the rapid and effective atomization and subsequent evaporation of the fuel. If this is not achieved with sufficient quality, increased levels of pollutants such as NOx, soot, or unburned hydrocarbons can be observed.
To address these challenges, additive manufacturing of a novel film-laying airblast injector for compact engine designs is currently being tested using selective laser melting. This process allows the integral production of complex structures without subsequent post-processing. As the initial film thickness has a significant influence on the resulting droplet diameter, the fuel outlet cross-section (see detail C) was optimized extensively. In the course of preliminary work, an outlet cross-section of approximately 40 µm in ring slit width was achieved. A total of nine different injectors with various measures to influence the airflow and liquid film were produced, which will now be comprehensively tested in the further course of the project.
We deliberately modulate the turbulence of the gas phase flow, e.g., using fractal grids and swirlers, with the objective of suppressing or exciting disturbances on the liquid surface to favour atomization into the smallest possible droplets. This project is currently ongoing.
To explore this relationship, we use various conventional and synthetic (SAF) fuels as well as reference fuels (e.g., n-dodecane) and systematically investigate the impact of physical fuel properties on spray quality for different injection concepts. This project is currently ongoing.
An increase in fuel temperature reduces viscosity, alters atomization and favours vaporisation process thereby potentially accelerating mixture homogenisation. In this context, we vary the preheating temperature of fuels from room temperature to supercritical injection. This project is currently being initiated.
The influence of vaporisation, especially in high-turbulence (and convective) flows with multi-component (real) fuels, on mixture formation with focus on emissions formation.
The influence of ambient conditions, such as pressure and temperature, on atomization, mixture formation, auto-ignition-based flame stabilisation, and emissions formation in turbulent reacting multiphase flows with high Karlovitz number.
Additional information / Get involved
If you are interested in our project, have further questions, or would like to support us through student work, internships, or thesis projects, we would be delighted to hear from you via email or phone. Contact details can be found below.
Contact
Fabian Hampp
Dr.Junior Research Group Leader