Particle image velocimetry measurements of internal combustion engine flows

Abstract

Studies have been undertaken to visualize and measure the valve jet associated with the intake process of reciprocating internal combustion engines. This initial work uses an intake flow simulator with the objective of an application to an engine simulator. The flow simulator has superior optical access, and its steady flow operation makes synchronization of the light source with the event we want to capture easier.Unlike Laser Doppler Anemometry (LDA), Particle Image Velocimetry (PIV) allows the researcher to map out the flow field of an extended two dimensional region simultaneously. In the current study, the flow is seeded with 0.3 μm aluminum oxide particles. A Nd:YAG laser is used as a light source. The flow is illuminated with a sheet of laser light of width 30 mm, thickness 0.2 mm and time duration 20 ns. The light scattered from the particles is recorded on Kodak 2415 Technical Pan film. Approximately 40 μs later, a second sheet of laser light illuminates the same field of view, and the scattered light is recorded on the same film. When the displacement of the particles from the first illumination to the second is determined, the velocity is found by: U→=ΔS→ΔtIn the present study, the imaged region measures approximately 30 by 20 mm. Velocity vectors are found for each 1 mm square. Thus each image can produce approximately 600 velocity vectors. Computer algorithms extract velocity information from the images.Studies have been undertaken to visualize and measure the valve jet associated with the intake process of reciprocating internal combustion engines. This initial work uses an intake flow simulator with the objective of an application to an engine simulator. The flow simulator has superior optical access, and its steady flow operation makes synchronization of the light source with the event we want to capture easier.Unlike Laser Doppler Anemometry (LDA), Particle Image Velocimetry (PIV) allows the researcher to map out the flow field of an extended two dimensional region simultaneously. In the current study, the flow is seeded with 0.3 μm aluminum oxide particles. A Nd:YAG laser is used as a light source. The flow is illuminated with a sheet of laser light of width 30 mm, thickness 0.2 mm and time duration 20 ns. The light scattered from the particles is recorded on Kodak 2415 Technical Pan film. Approximately 40 μs later, a second sheet of laser light illuminates the same field of view, and the scattered ...