A Numerical Study into the Effect of Cavitation Number on the Flow Characteristics in Diesel Nozzle Holes

摘要

The cavitating flow in nozzle holes is thought to be a very important factor to affect diesel fuel spray characteristics. In order to study the effect of cavitation on the internal flow of diesel nozzle, the 3d numerical simulation of cavitating flow developed fully in holes of a vertical four-hole VCO nozzle with mixture multi-phase cavitating flow model was carried out. The effects of injection pressure, needle lift, hole entrance curvature radius and hole inclination angle on the cavitating flow in nozzle holes were achieved. The investigation shows that the nozzle discharge coefficient depends mainly on cavitation number rather than on Reynolds number and the nozzle geometry heavily affects critical cavitation number, while injection pressure and needle lift has weaker effect on it.