ATOMIZATION CHARACTERISTICS OF JET-TO-JET AND SPRAY-TO-SPRAY IMPINGEMENT SYSTEMS

Atomization characteristics in a mutual-impingement spray system was investigated experimentally. The sprays injected from two conventional electronic fuel injection (EFI) nozzles or spraying nozzles were impinged at various impingement locations and impingement angles. When the impingement took place in the vicinity of the nozzle, a jet-to-jet impingement was observed, while a spray-to-spray impingement was observed in the case of mutual impingement of fully developed sprays which formed far away from the nozzle. The results showed that the spray tip penetration in the case of jet-to-jet impingement became short compared with that of the free spray (nonimpingement). On the other hand, in the case of spray-to-spray impingement, the spray tip penetration was almost the same as that of the free spray. Also, the reduction of Sauter mean diameter (SMD) was caused by the film disintegration after the impingement in both cases, jet-to-jet and spray-to-spray impingement. The SMD after the jet-to-jet impingement was approximately one-half of that of the free spray. In the case of the spray-to-spray impingement, it was observed that the liquid film was formed by the droplet collisions in the spray and the film disintegrated into many fine droplets. The SMD reduction after the spray-to-spray impingement was about 70−80% of that of the free spray.