INVESTIGATION OF HOT FILM JET VORTEX EFFECTS ON DROPLETS CHARACTERISTICS OVER AERO-ENGINE INLET STRUT

摘要

The jetted hot film could affect the trajectories of the water droplets near the aero-engine inlet strut surface, which equipped with the ice protection system combined the internal impingement heat transfer and the external hot air film heating. To evaluate the droplets impingement characteristics of four ice-protection structures designed with different film-slot jet angles, a droplets impingement computation method based on Eulerian framework was developed and validated. The influences of film-slot angle and blowing ratio on the impingement characteristics for droplet diameter of 20μm were investigated and the jet vortex was found to be an important factor. The results indicated that the local collection efficiency and the impingement limitation could decrease significantly due to the blowing from the external hot-film, and the influence would be more significant in case that the film-slot was closer to the leading edge. For example, the average local collection efficiencies of four typical configurations with different slot angles and positions decreased 82%, 8%, 1% and 0.5% respectively comparing to those without air film. Besides that, the maximum local collection efficiency and the impingement limitation decreased with the increasing blowing ratios, and the film-slot nearest to the leading edge was most sensitive to the blowing ratio. It was also found that no droplets impinged on the rear surface after the jet slots at some higher blowing ratios.