Numerical investigation on the effect of creating swirly flow inside the nozzle and injection pressure increase on the cavitation and diesel fuel spray characteristics

In this paper, the effect of changing geometry and creating swirly flow inside the injector nozzle and increase of injection pressure on the cavitation and resulted spray characteristics are investigated using Fire software. To this end, after simulating injector with cylinderical and conical nozzle holes and validating numerical resultswith experimental data, spiral rifling like guide inside the converged conical nozzle hole and different injection pressure have been used. Numerical results show that using spiral rifling like guide leads to increasing spray cone angle and decreasing penetration length and Sauter mean diameter. Also, increase of the injection pressure leads to increasing penetration length and decreasing spray cone angle and sauter mean diameter. Matlab software has been used in order to calculating the spray cone angle. The increased spray penetration length in this case may lead to impingement and bore wetting resulting increased hydrocarbon emissions and decreasing engine efficiency. Thus,the fuel spray characteristics can be controlled by changinenozzle geometry and injection pressure.