نویسندگان
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
In this work, result of experimental investigation on interaction of fuel spray generated by a swirled type injector,
with air motion in a prototype cylinder are presented. Experiments were carried out by planar imaging and particle
image velocimetry (PIV) techniques in order to provide information about the spray structure evolution and
instantaneous velocity distribution of air motion and fuel spray at different operating condition. The experimental
setup includes an engine head and a prototype cylinder with optical access suitable to stabilize conditions of tumble
flow close to the real SIDI engines. A common rail injection system was used with a swirled type injector of a nominal
cone angle 50° and a nozzle diameter 0.55 mm. A blower, under steady state condition, supplies a suitable intake flow
rate to simulate that one evolves in real engines at different operating conditions. Tests were carried out by setting the
pressure drop between the intake manifold and cylinder of 350 mm H2O, valve lifts and 9 mm and injection
pressure 10 MPa. The measurement, have been done on a plane across the cylinder and injector axis with a field of
view of 47 mm in diameter. PIV of air motion shows a fluid dynamics structure clockwise rotating with homogenous
structure. The velocity profiles show 30% increasing of maximum velocity at operating condition of mm with
respect to mm. At the first stage of injection, results of planar imaging show a fuel spray that depicts a solid
structure with a penetration axis primarily controlled by the fuel momentum at later time the fuel spray depicts a less
cone angle with respect to those obtained by analyzing the spray under air flow quiescent condition. Then, because of
tumble motion, the fuel spray is distorted and disintegrated. Images show the formation of large clusters of fuel which
are transferred in wide region within the cylinder. At the first stage of injection, PIV results of instantaneous velocity
distribution of fuel spray show a strong exchange of momentum with air motion evolving inside the cylinder. At later
time, velocity profiles of fuel droplets indicate a strong correlation with tumble motion that becomes the parameter
regulating breaking, dispersion and transferring liquid fuel in the periphery cylinder.
کلیدواژهها [English]
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