1. Effect of geometry of real-size transparent nozzles on cavitation and on the atomizing jet in the near field
- Author
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Jean-Bernard Blaisot, Saïd Idlahcen, Yujun Cao, Claude Rozé, Loïc Méès, David Maligne, Complexe de recherche interprofessionnel en aérothermochimie (CORIA), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU), Laboratoire de Mecanique des Fluides et d'Acoustique (LMFA), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), and Delphi Diesel Systems France
- Subjects
Materials science ,Nozzle ,Near and far field ,01 natural sciences ,Diesel injection ,diesel injection ,010305 fluids & plasmas ,Frecuency of cavitation ,0103 physical sciences ,Aerospace engineering ,backlight ,Index matching ,Jet (fluid) ,business.industry ,[SPI.FLUID]Engineering Sciences [physics]/Reactive fluid environment ,010401 analytical chemistry ,Backlight ,Liquid interface tracking ,0104 chemical sciences ,Real size ,frequency of cavitation ,Cavitation ,index matching ,[SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic ,liquid interface tracking ,business - Abstract
[EN] Cavitation inception is very sensitive to the nozzle geometry. Two diesel-like transparent nozzles with sharp and round inlet edge were investigated under moderate injection pressure. By means of backlight imaging technique, images were recorded in two regions near the orifice: within ten orifice diameter downstream the nozzle and inside the nozzle, for different times after start of the injection. A cross-correlation technique was applied to images downstream the orifice to estimate the average velocity of the spray. The development of the spray was studied at the transient and full-opened stage, related to the needle lift motion. To analyse the flow inside the nozzle, the relative size of the vapour pockets was measured on the image and the relative frequency of the occurrence of cavitation was determined over image series. This approach permits to examine the time variation of the cavitation occurrence from the inlet to the outlet of the orifice. The results highlight the sensitivity of the cavitating flow to the shape of the inlet edge. Moreover, the trends of the variation over time of the velocity and of the cavitation frequency are very similar to each other but different for each geometry, indicating that the characteristics of the diesel spray in the near field is closely affected by the way cavitation is developing in the nozzle., This work was supported by CANNEx program (ANR-13-TDMO-03), funded from French National Research Agency (ANR).
- Published
- 2017
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