Schlieren visualization of a GDI spray impacting on a heated wall: non-vaporizing and vaporizing evaluations

Autor: L.Allocca, M.Lazzaro, G.Meccariello, A.Montanaro
Jazyk: angličtina
Rok vydání: 2014
Předmět:
Zdroj: 7th International Conference on Sustainable Energy & Environmental Protection-SEEP2014, Dubai (Emirati Arabi), 23-25 novembre 2014
info:cnr-pdr/source/autori:L.Allocca, M.Lazzaro, G.Meccariello, A.Montanaro/congresso_nome:7th International Conference on Sustainable Energy & Environmental Protection-SEEP2014/congresso_luogo:Dubai (Emirati Arabi)/congresso_data:23-25 novembre 2014/anno:2014/pagina_da:/pagina_a:/intervallo_pagine
Popis: The Direct Injection (DI) in Spark Ignition (SI) engines is rapidly developing and seems being very attractive offering the possibility of multi-mode operation, homogeneous and stratified charge, with benefits respect to conventional S.I. engines. One of the major drawbacks of the GDI-fuelled engine is the impingement of liquid fuel on the combustion chamber wall that generally produces an increasing of HC emissions and effects on the combustion process like soot formation in the wall guided engines due to the fuel film deposits on the piston head. This paper investigates the structure of gasoline spray-wall interaction generated by a single-hole injector for GDI engine in an optically-accessible quiescent vessel. The axially-disposed hole diameter is 0.200 mm with a L/d ratio of 1.0 while the injection pressure and the wall temperature varied in the range of 10.0 - 20.0 MPa and ambient to 300 °C, respectively. Injection duration of 1.0 ms was investigated and the nozzle tip-wall distance was 22.5 mm. Optical investigations were carried out at atmospheric backpressure by a in-line schlieren optical setup using a LED source while the cycle-resolved images of the evolving impact were captured by a C-Mos high-speed camera with a time resolution of 80 ?s and a window size of 640x464 pixels. The optic-geometrical setup realized a spatial resolution of 25.50 pixel/mm. The images were treated by a digital processing software for background subtraction and both liquid and vapor contour extractions. The spatial and temporal evolution of the liquid and vapor phases as a function of the wall temperature is described for the different operative conditions.
Databáze: OpenAIRE
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