section-a572e1a
Previous LEAF studies at UCAM (at TRL1) and ETH (at TRL2) provided flame visualisation and emissions data. In FFLECS, these rigs will be upgraded for H₂ and dual-fuel operation and equipped with advanced optical diagnostics (OH*/CH* chemiluminescence, OH-/NO-PLIF, Mie scattering) to investigate NOx formation. ETH’s pressure vessel offers wide optical access, preheated air up to 8 bar, and operation up to 500 kW, including limited pure-H₂ operation.
Lean lifted spray flames previously studied at KIT will be adapted for dual-fuel H₂/SAF use. The modular test rig allows variable burner geometry, high inlet temperatures, and extensive optical measurements (high-frequency PIV, OH* chemiluminescence, shadowgraphy). Ion-probe data will support detection of near–lean-blowout conditions, and pollutant emissions will be measured across broad operating ranges.
UNINA will perform detailed PM measurements on both CHAIR and LEAF rigs using an SMPS system with controlled sampling. Common batches of ASTM-approved SAFs (HEFA-SPK and ATJ-SPK) will be distributed to all partners to ensure consistency across experiments.
UNINA will also develop a real-time PM sensor based on UV absorption (200–350 nm) to support active combustion control, enabling temperature-based stability assessment and PM detection. A lower-cost thermocouple-based PM estimation method will also be explored.
Plasma-assisted combustion tests at UCAM and UNILE will use ns-pulse and AC DBDs to separately study radical production and ion-wind effects, with flame imaging via OH* and CH* chemiluminescence.
Finally, experimental characterisation of primary spray breakup—needed for validation of CNRS simulations—will require advanced imaging beyond traditional shadowgraphy, including PLIF and two-photon LIF.