Numerical Investigation on the Influence of the Nozzle Geometry and Needle Lift Profile Simultaneous Change on Spray Behavior of Diesel Fuel in Injector

Cavitation phenomenon has destructive effects on the turbomachines performance but the occurrence of this phenomenon inside the injector nozzle has significant effect on the fuel spray hydrodynamic behavior. The nozzle geometry, needle lift profile and fuel type are effective parameters in creation of this phenomenon. The main goal and novelty of the present study is to investigate the effect of simultaneous change of the injector nozzle geometry and the needle lift profile on the creation of cavitation and diesel fuel spray hydrodynamic behavior. Thus in the first part, the liquid flow and spray characteristics of the cylindrical and converged conical nozzles with the same needle lift profile are investigated numerically using AVL-Fire CFD code. In the second step the converged conical nozzles with different needle lift profiles are simulated. Numerical results of the second part of this study show that the converged conical nozzles with different needle lift profiles have a longer spray penetration length and smaller Sauter-mean diameter than nozzles simulated in the first part of this study.