Surface Wave Propagation and Breakup in Planar Liquid Sheets of Prefilming Airblast Atomisers

Abstract

The liquid sheet breakup mechanism on a prefilming surface plays an important role in understanding the fuel placement in aeroengine combustors. Detailed knowledge of near-field and far-field characteristics of the spray is necessary for validation of spray combustion models incorporating airblast atomisers. An experimental approach is adopted in the present study to investigate the liquid sheet breakup mechanism on a prefilming surface and the characterisation of the spray. The liquid sheet breakup mechanism is studied by High-Speed Flow visualisation. Characterisation of the spray is carried out by PDA measurements. An effort is made to measure the near-field velocities of large structures with Particle Image Velocimetry. The sheet thickness on the prefilming surface is measured. The visualisation studies show that the liquid sheet breakup on the prefilming surface is different from the liquid sheet breakup without prefilmer surface. The PDA Measurements show that the relationship between Weber number and global SMD follows a power law. Application of PIV shows some promise in the acquisition of velocity data in the atomiser near-field.