Grid size optimization for diesel injection spray nozzle using CFD analysis

Abstract

In this chapter an experimental and numerical simulation were carried out for diesel spray to investigate its characteristics over a wide range of pressure. It would be helpful to predict the spray behavior such as penetration length, atomization, droplet distribution and spray angle for different pressure differences, covering low to high injection pressure. By knowing the behavior of injector over a pressure range gives a way to discover its applicability in a particular engine. The effect of various spray breakup models is studied and its influencing parameters like breakup length, breakup size constants were optimized iteratively. These parameters have a great influence in deciding the way in which the primary and secondary breakup occurring. Grid independency is done to have an optimized grid size by making a trade-off between accuracy and simulation time. Also the effect of discrete phase models (DPM), turbulence models and its constants, total parcels and maximum cells used for adaptive meshing were studied and compared with the test bench results. From the numerical simulation results, the optimum parameters were decided to predict the spray behavior closer to the test bench results.