High-Speed Measurements of Flame-Stabilization Processes in Vitiated Augmentor Environments for Understanding Screech, Rumble, and Blowoff

The proposed Phase-II research is a natural extension and a significant advancement over the Phase-I research, which has successfully demonstrated high-speed, burst-mode Tomo-PIV measurements synchronized with OH-PLIF imaging on a reacting propane jet in hot vitiated crossflows. We first propose to conduct a systematic and in-depth investigation of autoignition-assisted flame stabilization and flame propagation and flame/turbulence/acoustics/thermochemistry interactions on a transverse reacting propane jet by conducting high-speed, burst-mode Tomo-PIV measurements, dual-plane OH-PLIF imaging, two-color OH-PLIF thermometry, CH2O/OH-PLIF imaging as well as tomographic imaging of OH* chemiluminescence. This will generate unprecedented benchmark databases on turbulent combustion with unambiguous determination of the nine-component strain-rate tensor, the flame stretch rate, the flame curvature and the flame orientation. Then, we shall focus on jet breakup, atomization, evaporation, droplets/vapor/oxidizer mixing, spray autoignition and turbulent spray combustion at afterburner-realistic conditions by performing high-speed, burst-mode Tomo-PIV measurements, tomographic imaging of ligaments and droplets, OH/fuel-PLIF imaging, fiber-coupled illumination of the jet column as well as tomographic imaging of OH* chemiluminescence. The proposed research aims to substantially advance state-of-the-art understanding of turbulent combustion with both gaseous and liquid fuels, combustion instabilities, flame stabilization and blowoff in afterburners and other combustion/propulsion systems.