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論文
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ARAI, Masataka ; AMAGAI, Kenji ; NAKAJI, Takayuki ; HAYASHI, Shinji
概要:
application/pdf<br />Journal Article<br />Particulate matter (PM) emission exhausted from diesel engine should be reduced to keep the clean air environment. PM emission was considered that it consisted of coarse and
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aggregate particles, and nuclei-mode particles of which diameter was less than 50nm. However the detail characteristics about these particles of the PM were still unknown and they were needed for more physically accurate measurement and more effective reduction of exhaust PM emission. In this study, the size distributions of solid particles in PM emission were reported. PMs in the tail-pipe emission were sampled from three type diesel engines. Sampled PM was chemically treated to separate the solid carbon fraction from other fractions such as soluble organic fraction (SOF). The electron microscopic and optical-manual size measurement procedures were used to determine the size distribution of primary particles those were formed through coagulation process from nuclei-mode particles and consisted in aggregate particles. The centrifugal sedimentation method was applied to measure the Stokes diameter of dry-soot. Aerodynamic diameters of nano and aggregate particles were measured with scanning mobility particle sizer (SMPS). The peak aggregate diameters detected by SMPS were fallen in the same size regime as the Stokes diameter of dry-soot. Both of primary and Stokes diameters of dry-soot decreased with increases of engine speed and excess air ratio. Also, the effects of fuel properties and engine types on primary and aggregate particle diameters were discussed.
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論文
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TAKEDA, Chikashi ; OHTA, Yuji ; ISHIMA, Tsuneaki ; ISHII, Kiyoshi ; OBOKATA, Tomio
概要:
application/pdf<br />Journal Article<br />In order to measure flow velocity in the swirl and radial directions of a cylinder of an engine in practical use by means of a laser Doppler anemometer(LDA)through a small measuring window on the
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cylinder head, a back scattering fringe mode LDA is used. This LDA, however, can not be used to measure the velocity component in the axial direction of the cylinder. A single incidence-beam reference-mode LDA is developed to measure the velocity component along the optical axis of the LDA and is applied to measure the fluctuating flow velocity in the axial direction of the cylinder. Ensemble-averaged mean velocity and fluctuation intensity of the velocity as measured using the LDA show good agreement with those measured using the conventional fringe-mode LDA. Based on these results, it can be concluded that the reference-mode LDA is applicable to measurements of the flow velocity in the axial direction of the cylinder through the amall window on the cylinder head.
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論文
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TABATA, Michihiko ; FUJII, Hiroshi ; ARAI, Masataka ; HIROYASU, Hiroyuki
概要:
application/pdf<br />Journal Article<br />The Sauter mean diameter and size distribution of a diesel spray in a vaporizing process were studied to obtain detailed information of the diameter change of the spray in an
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elevated-temperature and-pressure environment. In this study, direct photographs of the diffracted light from particles or spray drops were taken using a pulsed laser and analyzed directly. The mean particle size could be measured even if the diffracted light from particles passed through a high-ambient-temperature and-pressure environment. The liquids used for studying a vaporizing diesel spray were diesel fuel and n-heptane. The Sauter mean diameter increased to a maximum, then decreased with a further increase of the ambient temperature. The change of the Sauter mean diameter was different for different fuel evaporation rates. The increase of the Sauter mean diameter of n-heptane spray occurred at a lower ambient temperature condition than did that for the diesel spray.
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