Fuel Atomization

The formation of a combustible mixture from liquid fuel, including the early phases of the jet break-up, atomization and homogenization is one of the major research areas of the Department. For a detailed analysis with optical and laser-based measurement techniques, a high pressure atomization test rig (OHA) is available. The test rig design is close to real combustor configurations and allows optical access for experiments at elevated pressures and pre-heat temperatures.

Besides addressing topics of fundamental research, the test rig is used to create validation data for CFD simulations by industrial and research partners.

With the support of the Engine Measurement Systems department of the DLR several measurement techniques have been applied successfully at the test rig and valuable information about fuel atomization were made accessible:

• Phase -Doppler-Anemometry (PDA) à Droplet size and velocity distribution Laser -Doppler-Anemometry (LDA) à Punctual measurement of flow field
• Tomographic-Shadowgraphy à Time resolved information about droplet velocities
• Mie-scattering à Qualitative measurement of liquid fuel placement
• High-Speed-Visualisation à Visualisation of break-up processes
• Particle-Image-Velocimetry  (PIV) à Flow field

Spatial droplet size distribution and spatial liquid fuel flux measured by PDA (Freitag, 2018)

Snapshot of 3-c droplet velocities in a volume obtained by Tomographic Shadowgraphy (Klinner et al., 2016)