Experimental and numerical investigations on internal flow characteristics of diesel nozzle under real fuel injection conditions

The internal flow characteristics of a single-hole diesel nozzle under the real fuel injection condition have been intensively explored through a combination of experimental measurements and numerical modeling with a two fluid approach. The pressure fluctuations upstream the nozzle hole, the evolution of cavitation content inside the nozzle hole and the mean dynamic behavior of local bubbles have been particularly analyzed. The results indicate that the pressure close to the inlet of nozzle hole fluctuates more drastically as the average injection pressure increases, and the internal flow of nozzle hole corresponding to the coexistence of pressure fluctuations and cavitation is inherently unsteady and complicated. It is of interest that the cavitation content and the liquid mass flow rate inside the nozzle hole indicate a close association with the variations of pressure change rate and pressure at the nozzle inlet, respectively, and as the spatial location of bubbles inside the nozzle hole obviously varies the mean dynamic behavior of these bubbles show distinct responses to upstream pressure fluctuations. (C) 2012 Elsevier Inc. All rights reserved.