Study on Spray Characteristics and 0-D Model of Marine Injector with Large Orifice Diameter

Abstract

ABSTRACT Low carbon, cleanliness and efficiency are the three key challenges facing the development of diesel engines. Biodiesel is a crucial step in the transition from fossil fuels to zero-carbon fuels. This study was carried out to investigate the effects of injection pressure and ambient pressure on the biodiesel spray characteristics of a marine large orifice diameter injector. Injection mass has a nonlinear relationship with short injection duration and a linear relationship with long injection duration. Increasing the injection pressure shortens the nonlinear stage and enhances the linear effect. When the injection pressure is increased from 35 MPa to 140 MPa, the injection delay is shortened by 10% (2.5 ms), and the diameter nozzle has almost unaffected on the injection delay. The Arai model was revised based on experimental data to improve its prediction effect on sprays with large nozzle diameters. The new model considers the effects of fuel density and ambient density on penetration before and after breakup, respectively. The penetration of the new model is still proportional to time of after start of injection (t) before the breakup and proportional to t0.6 after the breakup. Increasing the ambient pressure enhances the influence of injection conditions on dimensionless penetration. Compared with the Arai model, the new model reduces the sensitivity of the dimensionless penetration to the injection pressure. Research on biodiesel spray and spray models under large nozzle diameter conditions will be of great help to the application of low-carbon and clean fuels in marine diesel engines.