Effect of impinging angle on non-evaporative diesel wall-jet

This paper presents an experimental study on the wall-impinging diesel spray issued from a single-hole nozzle. To examine the effect of impingement angle on spray-wall interaction, repeated non-evaporative diesel spray is injected at 150 MPa pressure and impinged on a wet flat steel plate placed at a characteristic length where spray reaches peak velocity in the pressure chamber at 5 MPa in ambient temperature. The flow regimes resulting from the impact is closely observed by an ultra-high-speed camera. It is found that, spray-wall impact causes a huge loss of kinetic energy and reduces wall-jet penetration distance over the wall compared to free-jet. Wall-jet velocity slows down as a decaying turbulent jet as it travels further from the impinging point entraining more air and getting effected by growing aerodynamic drag. Compared to normally impinging sprays, wall-jet produced by higher impinging angle travels faster and breaks up its dense zones by diffusing easily into chamber. A new empirical formula is developed to express temporal evolution of radial wall-jets considering pressure gradient of issued spray, incident angle on solid wet plate and impingement distance.