The Impact of Cylinder Pressure on Fuel Jet Penetration and Mixing/Computational Modeling of Natural Gas Injection in a Large Bore Engine
Investigations of fuel jet penetration and fuel and air mixing are performed in a static piston, pressurized optical engine. The pressure in the cylinder that the gas is injected into is varied to study the effect of the compression process. The engine has the same piston and cylinder geometry as a Cooper-Bessemer GMV-4TF two-stroke cycle natural gas engine. A 14 quartz cylinder section allows the cylinder gases to be radiated with an Nd:YAG UV laser and imaged with an ICCD camera. Nitrogen gas that is seeded with acetone, which fluoresces in the visible range with irradiated with UV light, is injected through the fuel valves. Two types of fuel injectors are studied, a low pressure (45 psi) and a high pressure (500 psi) gas injection valve. Both fuel injection valves are manufactured by Woodward Governor. Planar laser induced fluorescence is implemented to image fuel concentration within the cylinder at various times during the injection and mixing processes. Spatial standard deviations of the variations of fuel concentration (unmixedness) and the volume fraction of gas in the flammable range (mixedness) across the image plane are computed. The results are correlated with differences in performance from on-engine testing for the two different fuel injectors.