Impact of nozzle and spray-hole design on mixture formation at medium-speed diesel engines
The current study is motivated by the upcoming IMO-Tier 3 emission legislation demanding a drastic cut in NOx-emissions. Injectors with a cylindrical and two conical nozzle geometries were studied in order to identify features that comply with the overall strategy of engine-internal emission reduction using exhaust gas recirculation. The work is concerned with a numerical analysis of the nozzle internal flow and the spray break-up depending on the geometric parameters of three different nozzles. For the simulation a 1D-hydraulic model of the injector was coupled with a 3D-CFD-calculation of the nozzle internal flow and the spray simulation. All models applied have been developed and calibrated using a reference configuration which was experimentally investigated at an injection rate analyzer and a high-pressure, high-temperature injection chamber. The simulated results of the reference set-up are in good agreement with the experiments proving the suitability of the models and calibration. Comparing the calculations, distinct differences in the nozzle internal flow field and spray penetration were found especially between the cylindrical and conical geometries. While increasing the conicity from k=0 to k=3 reveals apparent changes of the nozzle internal flow and spray characteristics, a further rise of conicity from k=3 to k=6 did not show any significant changes. Based on the obtained results it can be assumed, that alternative nozzle geometries may induce a positive impact on emissions of medium speed diesel engines. In the framework of the ongoing research project FAME an experimental study of the investigated nozzles will be performed at a highpressure, high-temperature injection chamber and a single cylinder research engine giving the opportunity to validate the results and conclusions presented in this paper.
Fabian Pinkert Ibrahim Najar Carsten Schmalhorst Moritz Frobenius Christian Fink Horst Harndorf
University of Rostock,Germany AVL Deutschland,Germany
国际会议
上海
英文
1-9
2013-05-13（万方平台首次上网日期，不代表论文的发表时间）