Publication de 12 numéros par an
ISSN Imprimer: 1044-5110
ISSN En ligne: 1936-2684
Indexed in
ANALYSIS OF PRE-IGNITION MECHANISMS IN A DIESEL COMBUSTION ENGINE WITH THE AID OF IMAGE PROCESSING
RÉSUMÉ
Simple image processing procedures have been applied to assist the study of unsteady diesel sprays, which represents one of the most difficult two-phase flow configurations to analyze by means of a nonintrusive method such as optical diagnostics. The first problem considered is rejection of the background for easier pattern recognition, or for automatic analysis of the image, which can be required for further elaboration. Simple image elaboration procedures are shown in order to assess the possibility of obtaining clean, purged images, which carry information only about the investigated area. The second problem considered is the restitution of images on linear scales, so that they can be analyzed by means of false-color representation. This operation is useful mainly when the range of gray levels in the image is compressed, i.e., in those cases for which the human visual system fails to detect repeatable, slight, spatially resolved, gray-level variations. The procedures are used in the analysis of a set of pictures, obtained at different crank angles in a diesel engine, from which some peculiar pre-ignition mechanisms can be inferred. The analysis of the spray evolution demonstrates the relevance of wall impingement. Considerations of mechanisms of ignition and flame propagation are also reported.
-
Ragucci R., Cavaliere A., Ciajolo A., D'anna A., D'alessio A., Structures of diesel sprays in isobaric combustion conditions, Symposium (International) on Combustion, 24, 1, 1992. Crossref