Numerical simulation of needle movement nozzle flow coupled with spray for a diesel injector using an Eulerian spray atomization model

The injector dynamics have a strong impact on spray behavior, therefore, on combustion efficiency, and pollutant emissions. Nozzle flow and spray coupled simulations are useful tools to analyze the effect of nozzle geometry, and they could be used also to study the effect of needle movement. In this work, three different approximations to the same needle lift law are employed in an Eulerian spray atomization model. The main advantage of this model is that is able to simulate nozzle flow and spray seamlessly. Engine combustion network Spray A conditions are simulated. Results show that the experimental needle lift law can be used without any fitting to a smoothed expression, but all details of the needle dynamics must be considered to properly predict mass flow rate and spray penetration. In addition, it has been shown that needle dynamics has a strong impact on heating effects inside the nozzle.