The Effect of Fuel Injector Nozzle Configuration on JP-8 Sprays at Diesel Engine Conditions

Report No. ARL-RP-0510
Authors: Matthew Kurman; Luis Bravo; Chol-Bum Kweon; Michael Tess
Date/Pages: October 2014; 20 pages
Abstract: The effect of injector nozzle configuration on liquid and vapor penetration lengths of JP-8 sprays was investigated. Non-reacting spray experiments were conducted in a high temperature (900 K), high pressure (60 bar) flow-through chamber which simulates realistic conditions found in compression-ignition engines. Three different Bosch CRIN3 fuel injectors consisting of a 1-hole axial, a 2-hole adjacent (spaced 60°), and a 6-hole (spaced 60°) nozzle configuration were used for the study. Prior to conducting the spray studies, each fuel injector was mapped with an injection analyzer to ensure consistent fuel delivery between injectors. For the experiments, fuel rail pressure was maintained at 1000 bar at two different fuel injection durations consisting of 0.45 ms and 0.7 ms, representing low and high loads. High-speed Mie and schlieren images were acquired and processed using LaVision software for the three different nozzle configurations. Furthermore, high-speed axial Mie scattering images were acquired for the 2 and 6-hole injectors. Results show that the 1-hole and 6-hole injectors have a quasi-steady liquid penetration length of 20 mm and for the 2-hole injector the liquid length was 15 mm. Results from the injector mapping revealed that fuel mass does not scale linearly with the increase in the number of orifices. The liquid penetration rate was similar for the 1 and 2-hole injectors, however, slower for the 6-hole injector. Plume to plume liquid length variations were present for both the 2 and 6-hole injectors. However, the 6-hole presented more variations than the other injectors tested. In addition, a 3D CFD study was conducted to compare modeling to experimental results. Fuel spray studies investigating liquid and vapor penetrations lengths can be useful to increase atomization and vaporization, thus ultimately improving combustion and fuel efficiency.
Distribution: Approved for public release
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Last Update / Reviewed: October 1, 2014